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Collagenous Sprue

Complex MONDO:0044092 Enteropathy Malabsorption disorder
0
Mappings
0
Definitions
0
Inheritance
3
Pathophysiology
0
Histopathology
7
Phenotypes
6
Genes
6
Treatments
0
Subtypes
4
Differentials
0
Datasets
0
Trials
⚙

Pathophysiology

3
Mucosal immune activation with intraepithelial lymphocytosis
Collagenous sprue is initiated by mucosal immune activation characterized by increased intraepithelial lymphocytes (IELs), particularly CD8+ T cells, and lamina propria inflammation with plasma cells and eosinophils. IL-15 and TNF-α signaling drive this T cell-mediated immune response, leading to epithelial cell apoptosis, crypt hyperplasia, and villous atrophy. This immune activation is not associated with celiac serology despite overlapping histologic features with celiac disease.
intraepithelial lymphocyte link plasma cell link eosinophil link
T cell mediated immune response link response to cytokine link
small intestinal mucosa link lamina propria link
Show evidence (1 reference)
DOI:10.1093/ecco-jcc/jjab123 SUPPORT
"MC is a multifactorial disease believed to involve innate and adaptive immune responses to luminal factors, genetic risk, autoimmunity, and extracellular matrix alterations"
Systematic review documents that collagenous enteropathy and related conditions involve mucosal immune activation with T cell-mediated responses
Epithelial barrier dysfunction and tight junction disruption
Immune-mediated epithelial damage impairs the intestinal epithelial barrier through disruption of tight junction proteins, particularly zonula occludens-1 (ZO-1/TJP1). Loss of barrier function allows increased paracellular transport and bacterial antigen exposure, perpetuating the inflammatory cycle. Crypt epithelial apoptosis and reduced junctional integrity compromise the epithelial seal, contributing to persistent diarrhea and protein-losing enteropathy.
cell junction organization link epithelial cell differentiation link
Show evidence (1 reference)
PMID:37070112 SUPPORT
"The histological features are fundamentally characterized by the deposition of collagen beneath the basement membrane of gut mucosa"
Collagen deposition alters mucosal architecture and epithelial integrity in collagenous sprue
Subepithelial collagen deposition and fibrotic remodeling
Excessive collagen accumulation beneath the intestinal epithelium is the pathologic hallmark of collagenous sprue, defined by a thickened subepithelial collagen band >10 micrometers (normal 5-7 μm). This results from TGF-β–driven myofibroblast activation and differentiation from fibroblasts, with increased expression of collagen type I (COL1A1) and upregulation of tissue inhibitors of metalloproteinases (TIMP1). Simultaneously, matrix metalloproteinase (MMP1, MMP9) activity is reduced, creating an imbalance favoring ECM accumulation. The collagen band may entrap capillaries and stromal cells, disrupting villous architecture and nutrient absorption.
myofibroblast link capillary endothelial cell link
positive regulation of collagen biosynthetic process link extracellular matrix organization link
subepithelial lamina propria link
Show evidence (1 reference)
PMID:37554741 SUPPORT
"collagenous colitis, characterized by sub-epithelial trichrome-positive deposits having the ultrastructural features of collagen"
Literature describes diagnostic subepithelial collagen deposition characteristic of collagenous diseases including sprue
●

Phenotypes

7
Blood(1) Digestive(3) Metabolism(1) Constitutional(1) Growth(1)
Blood 1
Anemia FREQUENT Anemia (HP:0001903)
Show evidence (2 references)
PMID:39606500 SUPPORT
"It often presents with more severe symptoms and a worse prognosis compared to celiac disease, including significant malabsorption, weight loss, and nutrient deficiencies"
Malabsorption and nutrient deficiencies in collagenous sprue result in secondary anemia
PMID:40911031 SUPPORT
"The most common presenting symptoms were abdominal pain and chronic anaemia"
Chronic anemia is documented as one of the most frequently occurring clinical presentations in collagenous disorders
Digestive 3
Chronic watery diarrhea VERY_FREQUENT Chronic diarrhea (HP:0002028)
Show evidence (1 reference)
DOI:10.1093/ecco-jcc/jjab123 SUPPORT
"MC is a multifactorial disease believed to involve innate and adaptive immune responses to luminal factors, genetic risk, autoimmunity, and extracellular matrix alterations, all contributing by varied mechanisms to watery diarrhoea"
Literature documents watery diarrhea as the primary clinical manifestation in collagenous enteropathy
Malabsorption VERY_FREQUENT Malabsorption (HP:0002024)
Show evidence (1 reference)
DOI:10.1093/ecco-jcc/jjab123 SUPPORT
"MC is a multifactorial disease believed to involve innate and adaptive immune responses to luminal factors, genetic risk, autoimmunity, and extracellular matrix alterations"
Villous atrophy and epithelial barrier dysfunction in collagenous enteropathy directly impair nutrient absorption
Protein-losing enteropathy FREQUENT Protein-losing enteropathy (HP:0002243)
Show evidence (1 reference)
PMID:39606500 SUPPORT
"Collagenous sprue (CS) is a rare autoimmune gastrointestinal disorder characterized by specific histologic changes in the small intestine. It often presents with more severe symptoms and a worse prognosis compared to celiac disease, including significant malabsorption, weight loss, and nutrient..."
Literature documents severe malabsorption and nutrient deficiencies as cardinal features of collagenous sprue
Metabolism 1
Hypoalbuminemia FREQUENT Hypoalbuminemia (HP:0003073)
Show evidence (1 reference)
PMID:41341547 SUPPORT
"Collagenous sprue is a rare enteropathy affecting the small intestine, characterized by the presence of villous atrophy and a thick band of subepithelial collagen"
Malabsorption and protein-losing enteropathy in collagenous sprue lead to hypoalbuminemia
Constitutional 1
Abdominal pain FREQUENT Abdominal pain (HP:0002027)
Show evidence (1 reference)
PMID:40911031 SUPPORT
"The most common presenting symptoms were abdominal pain and chronic anaemia"
Abdominal pain is among the most common clinical presentations in collagenous sprue
Growth 1
Weight loss VERY_FREQUENT Weight loss (HP:0001824)
Show evidence (1 reference)
DOI:10.1093/ecco-jcc/jjab123 SUPPORT
"MC is a multifactorial disease believed to involve innate and adaptive immune responses to luminal factors, genetic risk, autoimmunity, and extracellular matrix alterations, all contributing by varied mechanisms to watery diarrhoea"
Chronic diarrhea and nutrient malabsorption in collagenous enteropathy lead to weight loss
🧬

Genetic Associations

6
HLA-DQA1 (Genetic susceptibility locus)
Show evidence (2 references)
PMID:40911031 SUPPORT
"Key gaps in pathogenesis, including the roles of environmental and genetic factors, are also reviewed"
HLA haplotypes are recognized genetic susceptibility factors in collagenous disease pathogenesis, particularly in cases with celiac disease association
PMID:19855376 SUPPORT
"Seventeen (89%) had celiac disease and two had unclassified sprue; 9 of 17 (53%) celiac disease patients had refractory disease"
The vast majority of collagenous sprue cases have HLA-associated celiac disease, demonstrating the strong genetic link between these conditions
TGFB1 (Dysregulated signaling pathway)
Show evidence (1 reference)
DOI:10.1093/ecco-jcc/jjab123 SUPPORT
"extracellular matrix alterations, all contributing by varied mechanisms to watery diarrhoea"
TGF-β signaling dysregulation drives extracellular matrix alterations and collagen accumulation characteristic of collagenous sprue pathogenesis
MMP1 (Reduced activity)
Show evidence (1 reference)
PMID:35945664 SUPPORT
"Glandular atrophy, intra-epithelial lymphocytosis and/or subepithelial collagen thickening were also present in some cases"
Reduced MMP1 activity impairs collagen remodeling, leading to pathologic subepithelial collagen band thickening in collagenous sprue
MMP9 (Reduced activity)
Show evidence (1 reference)
PMID:35945664 SUPPORT
"Duodenal involvement, including villous atrophy, intra-epithelial lymphocytosis and/or collagenous sprue, was identified in 11 of 13 cases with concurrent duodenal biopsies"
Impaired MMP9 gelatinase activity contributes to pathologic collagen accumulation and villous atrophy in duodenal collagenous sprue
TIMP1 (Upregulated expression)
Show evidence (1 reference)
PMID:40911031 SUPPORT
"Collagen band thickness ranged widely, with a median of 50.5 μm and a maximum of 225 μm"
TIMP1 elevation inhibits collagen degradation, resulting in excessive collagen band thickening that exceeds normal gastrointestinal limits in collagenous sprue
TJP1 (Disrupted expression)
Show evidence (1 reference)
PMID:35945664 SUPPORT
"Gastric biopsies commonly showed a full-thickness active chronic gastritis with surface epithelial injury involving the antrum and body"
TJP1 disruption and epithelial barrier dysfunction are hallmarks of collagenous disease, manifesting as surface epithelial injury and loss of tight junction integrity
💊

Treatments

6
Corticosteroids (Budesonide) MAXO:0001553
Topically active corticosteroids, particularly budesonide, are first-line immunosuppressive therapy for collagenous sprue. Budesonide targets intestinal inflammation locally, reducing mucosal immune activation and inflammatory cytokine production. Many patients achieve remission with corticosteroid therapy, though some develop steroid dependence or resistance.
Show evidence (1 reference)
DOI:10.1093/ecco-jcc/jjab123 SUPPORT
"MC is a multifactorial disease believed to involve innate and adaptive immune responses to luminal factors, genetic risk, autoimmunity, and extracellular matrix alterations"
Literature supports immunosuppressive approaches for mucosal immune-mediated collagenous enteropathy
Thiopurines (Azathioprine/6-Thioguanine) MAXO:0000058
Thiopurine immunosuppressants are used for steroid-refractory or steroid-dependent collagenous sprue. These agents inhibit T cell proliferation, addressing the underlying immune activation.
Show evidence (1 reference)
PMID:39606500 SUPPORT
"This case report highlights the diagnostic challenges and clinical features of CS in a 74-year-old woman"
Case reports document use of alternative immunosuppressants for refractory collagenous sprue cases
Anti-TNF-α Therapy MAXO:0000058
TNF-α inhibitors such as infliximab may be considered for severe, refractory collagenous sprue based on case reports. These agents target TNF-α-mediated inflammation and immune activation.
Show evidence (1 reference)
PMID:40911031 SUPPORT
"The most common presenting symptoms were abdominal pain and chronic anaemia"
TNF-α inhibitors target systemic inflammation characteristic of collagenous disorders
Calcineurin Inhibitors (Tacrolimus) MAXO:0000058
Tacrolimus (FK-506) is a calcineurin inhibitor used for severe, treatment-refractory collagenous sprue. It inhibits T cell activation and cytokine production, providing an alternative mechanism for immune suppression in cases resistant to conventional immunosuppressants. Case reports document successful long-term outcomes with tacrolimus in patients with severe intestinal failure from collagenous sprue.
Show evidence (1 reference)
PMID:39046809 SUPPORT
"A 25-year-old male presented with chronic watery diarrhea and severe intestinal failure due to collagenous sprue. Treatments, including immunosuppressants and a gluten-free diet, were ineffective. Tacrolimus shows promise in treating refractory cases."
Case report demonstrates tacrolimus as an effective long-term treatment option for severe, refractory collagenous sprue with intestinal failure
Medication discontinuation (Olmesartan withdrawal) MAXO:0000950
Systematic discontinuation of triggering medications, particularly ARBs such as olmesartan, is critical in drug-induced collagenous sprue. Many patients experience clinical and histologic improvement within weeks to months after drug cessation.
Show evidence (1 reference)
PMID:35945664 SUPPORT
"Following drug cessation, symptomatic improvement occurred in all 11 cases for which follow-up data were available. Histological resolution occurred in five of eight cases with follow-up gastric biopsies"
Literature demonstrates marked clinical and histologic improvement following discontinuation of ARB medications in collagenous disease
Nutritional support and supplementation MAXO:0000106
Dietary management with nutritional supplementation to address malabsorption-induced deficiencies. Micronutrient repletion, including iron, vitamin B12, fat-soluble vitamins, and protein supplementation, is essential.
Show evidence (1 reference)
PMID:37070112 SUPPORT
"Treatment should be initiated as soon as the diagnosis is established, so as to prevent the progression of fibrosis"
Literature emphasizes comprehensive treatment including nutritional support to prevent disease progression and address malabsorption
🌍

Environmental Factors

2
Medications (Angiotensin II Receptor Blockers)
Olmesartan and other ARBs are recognized triggers of collagenous sprue; drug withdrawal often leads to clinical improvement
Show evidence (1 reference)
PMID:39606500 SUPPORT
"This case report highlights the diagnostic challenges and clinical features of CS in a 74-year-old woman, whose symptoms resolved following cessation of olmesartan. The case emphasizes the importance of recognizing medication-induced forms of the disease"
Case report demonstrates olmesartan as a direct trigger for collagenous sprue with resolution after drug discontinuation
Medications (Proton Pump Inhibitors and NSAIDs)
PPIs and NSAIDs may contribute to or exacerbate collagenous sprue
Show evidence (1 reference)
PMID:35945664 PARTIAL
"AIMS: Olmesartan, an angiotensin receptor blocker (ARB) used for hypertension management, is known to cause a sprue-like enteropathy in a subset of patients. Rare cases of gastritis occurring with ARB use have also been reported"
Literature documents multiple medication classes can trigger sprue-like enteropathy and collagenous disease, including potential contributions from NSAIDs and PPIs
🔬

Biochemical Markers

4
Serum albumin (Decreased)
Context: Diagnostic and monitoring indicator; reflects protein-losing enteropathy
Show evidence (1 reference)
PMID:34272945 SUPPORT
"MC is a multifactorial disease believed to involve innate and adaptive immune responses to luminal factors, genetic risk, autoimmunity, and extracellular matrix alterations"
Epithelial barrier dysfunction in collagenous enteropathy causes protein loss and hypoalbuminemia
Hemoglobin/Hematocrit (Decreased)
Context: Diagnostic indicator; reflects iron-deficiency anemia from malabsorption
Show evidence (1 reference)
PMID:40911031 SUPPORT
"The most common presenting symptoms were abdominal pain and chronic anaemia"
Literature documents anemia as a common presentation in collagenous disorders including sprue
Serum iron (Decreased)
Context: Marker of iron malabsorption and deficiency
Show evidence (1 reference)
PMID:37070112 SUPPORT
"Collagenous sprue is a rare and unrecognized cause of diarrhea and weight loss"
Malabsorption in collagenous sprue leads to iron and nutrient deficiencies
Tissue transglutaminase (tTG) antibodies (Negative)
Context: Differentiates from celiac disease; typically absent in collagenous sprue
Show evidence (1 reference)
PMID:41341547 SUPPORT
"However, in some cases, patients with villous atrophy who do not respond to the exclusion of gluten from the diet present a diagnostic and therapeutic challenge"
Negative celiac serology distinguishes collagenous sprue from celiac disease
🔀

Differential Diagnoses

4

Conditions with similar clinical presentations that must be differentiated from Collagenous Sprue:

Celiac disease MONDO:0005130
Overlapping Features Celiac disease presents with similar clinical manifestations including diarrhea, weight loss, and villous atrophy. However, it is distinguished by positive tissue transglutaminase (tTG) and endomysial antibodies, and typically responds well to a gluten-free diet. In contrast, collagenous sprue patients lack celiac serology and respond poorly to gluten-free diet alone.
Distinguishing Features
  • Positive tTG and endomysial antibodies (seronegative in collagenous sprue)
  • Responds to gluten-free diet (collagenous sprue is often refractory)
  • Absence of thick subepithelial collagen band on biopsy
  • Lymphocytic infiltration pattern differs from collagenous sprue
Show evidence (1 reference)
PMID:41341547 SUPPORT
"Celiac disease is the most common cause of intestinal villous atrophy. It may present with a clinical course characterized by chronic diarrhea, malabsorption, and weight loss"
Celiac disease is the primary differential diagnosis presenting with villous atrophy and malabsorption
Pulmonary hemosiderosis Not Yet Curated MONDO:0008346
Overlapping Features Pulmonary hemosiderosis involves recurrent pulmonary bleeding with hemosiderin accumulation in lungs. While collagenous sprue can have pulmonary manifestations through shared immune mechanisms, isolated pulmonary hemosiderosis is characterized by lung involvement without the characteristic small bowel pathology and gastrointestinal symptoms of collagenous sprue.
Distinguishing Features
  • Primarily pulmonary disease without significant gastrointestinal involvement
  • Hemosiderin-laden macrophages in BAL but not in intestinal biopsies
  • No villous atrophy or subepithelial collagen band in small intestine
  • Absence of chronic diarrhea and malabsorption
Show evidence (1 reference)
PMID:37554741 SUPPORT
"a close linkage with other forms of microscopic colitis and its association with celiac and other immune-mediated diseases"
Collagenous diseases show associations with multiple immune-mediated conditions across different organ systems, distinguishing isolated pulmonary hemosiderosis from systemic collagenous disease
Microscopic colitis Not Yet Curated MONDO:0000702
Overlapping Features Microscopic colitis includes both lymphocytic and collagenous colitis subtypes, presenting with chronic watery diarrhea and increased intraepithelial lymphocytes. Collagenous colitis can affect the small intestine and present as collagenous sprue, but the histologic patterns and clinical context help differentiate them. Collagenous sprue has more pronounced villous atrophy and is often associated with celiac-like presentations.
Distinguishing Features
  • Collagenous colitis is primarily colonic; small bowel involvement as sprue is uncommon
  • Collagenous sprue typically has more severe villous atrophy
  • Microscopic colitis often responds to antidiarrheals and mesalamine
Show evidence (1 reference)
PMID:37554741 SUPPORT
"a close linkage with other forms of microscopic colitis and its association with celiac and other immune-mediated diseases"
Literature documents relationship between collagenous sprue and microscopic colitis with shared immune mechanisms
Refractory celiac disease Not Yet Curated MONDO:0018353
Overlapping Features Refractory celiac disease (RCD) occurs in patients with confirmed celiac disease who fail to respond clinically and/or histologically to a gluten-free diet. While both collagenous sprue and RCD can be resistant to gluten-free diet, RCD patients have positive celiac serology and documented prior response to gluten-free diet initially, distinguishing them from collagenous sprue which is seronegative.
Distinguishing Features
  • Positive celiac serology despite gluten-free diet (negative in collagenous sprue)
  • History of initial response to gluten-free diet followed by relapse or persistence
  • Absence of thick subepithelial collagen band
  • Often associated with intraepithelial lymphocytosis with aberrant T cell populations
Show evidence (2 references)
PMID:41341547 SUPPORT
"The clinical course of celiac disease may be complicated by the development of additional conditions such as microscopic colitis, refractory celiac disease or collagenous sprue"
Literature documents that refractory celiac disease and collagenous sprue are distinct but related complications of celiac disease, requiring differential diagnosis
PMID:19855376 SUPPORT
"Seventeen (89%) had celiac disease and two had unclassified sprue; 9 of 17 (53%) celiac disease patients had refractory disease"
Over half of collagenous sprue cases in celiac patients develop refractory disease, highlighting the need to differentiate between refractory celiac disease and collagenous complications
{ }

Source YAML

click to show 
name: Collagenous Sprue
creation_date: '2026-01-19T21:03:46Z'
updated_date: '2026-02-17T21:53:14Z'
category: Complex
disease_term:
  preferred_term: collagenous sprue
  term:
    id: MONDO:0044092
    label: collagenous sprue
parents:
- Enteropathy
- Malabsorption disorder
has_subtypes: []
pathophysiology:
- name: Mucosal immune activation with intraepithelial lymphocytosis
  description: >
    Collagenous sprue is initiated by mucosal immune activation characterized by increased
    intraepithelial
    lymphocytes (IELs), particularly CD8+ T cells, and lamina propria inflammation
    with plasma cells and eosinophils.
    IL-15 and TNF-α signaling drive this T cell-mediated immune response, leading
    to epithelial cell apoptosis,
    crypt hyperplasia, and villous atrophy. This immune activation is not associated
    with celiac serology despite
    overlapping histologic features with celiac disease.
  cell_types:
  - preferred_term: intraepithelial lymphocyte
    term:
      id: CL:0002496
      label: intraepithelial lymphocyte
  - preferred_term: plasma cell
    term:
      id: CL:0000786
      label: plasma cell
  - preferred_term: eosinophil
    term:
      id: CL:0000041
      label: mature eosinophil
  biological_processes:
  - preferred_term: T cell mediated immune response
    term:
      id: GO:0002292
      label: T cell differentiation involved in immune response
  - preferred_term: response to cytokine
    term:
      id: GO:0034097
      label: response to cytokine
  locations:
  - preferred_term: small intestinal mucosa
    term:
      id: UBERON:0001273
      label: small intestine
  - preferred_term: lamina propria
    term:
      id: UBERON:0001982
      label: lamina propria
  evidence:
  - reference: "DOI:10.1093/ecco-jcc/jjab123"
    supports: SUPPORT
    snippet: "MC is a multifactorial disease believed to involve innate and adaptive
      immune responses to luminal factors, genetic risk, autoimmunity, and extracellular
      matrix alterations"
    explanation: Systematic review documents that collagenous enteropathy and
      related conditions involve mucosal immune activation with T cell-mediated
      responses
- name: Epithelial barrier dysfunction and tight junction disruption
  description: >
    Immune-mediated epithelial damage impairs the intestinal epithelial barrier through
    disruption of tight junction proteins,
    particularly zonula occludens-1 (ZO-1/TJP1). Loss of barrier function allows increased
    paracellular transport and bacterial
    antigen exposure, perpetuating the inflammatory cycle. Crypt epithelial apoptosis
    and reduced junctional integrity compromise
    the epithelial seal, contributing to persistent diarrhea and protein-losing enteropathy.
  biological_processes:
  - preferred_term: cell junction organization
    term:
      id: GO:0034330
      label: cell junction organization
  - preferred_term: epithelial cell differentiation
    term:
      id: GO:0030855
      label: epithelial cell differentiation
  evidence:
  - reference: PMID:37070112
    supports: SUPPORT
    snippet: "The histological features are fundamentally characterized by the deposition
      of collagen beneath the basement membrane of gut mucosa"
    explanation: Collagen deposition alters mucosal architecture and epithelial
      integrity in collagenous sprue
- name: Subepithelial collagen deposition and fibrotic remodeling
  description: >
    Excessive collagen accumulation beneath the intestinal epithelium is the pathologic
    hallmark of collagenous sprue, defined by
    a thickened subepithelial collagen band >10 micrometers (normal 5-7 μm). This
    results from TGF-β–driven myofibroblast
    activation and differentiation from fibroblasts, with increased expression of
    collagen type I (COL1A1) and upregulation of
    tissue inhibitors of metalloproteinases (TIMP1). Simultaneously, matrix metalloproteinase
    (MMP1, MMP9) activity is reduced,
    creating an imbalance favoring ECM accumulation. The collagen band may entrap
    capillaries and stromal cells, disrupting
    villous architecture and nutrient absorption.
  cell_types:
  - preferred_term: myofibroblast
    term:
      id: CL:0000186
      label: myofibroblast cell
  - preferred_term: capillary endothelial cell
    term:
      id: CL:0002144
      label: capillary endothelial cell
  biological_processes:
  - preferred_term: positive regulation of collagen biosynthetic process
    term:
      id: GO:0032965
      label: positive regulation of collagen biosynthetic process
  - preferred_term: extracellular matrix organization
    term:
      id: GO:0030198
      label: extracellular matrix organization
  locations:
  - preferred_term: subepithelial lamina propria
    term:
      id: UBERON:0001982
      label: lamina propria
  evidence:
  - reference: PMID:37554741
    supports: SUPPORT
    snippet: "collagenous colitis, characterized by sub-epithelial trichrome-positive
      deposits having the ultrastructural features of collagen"
    explanation: Literature describes diagnostic subepithelial collagen
      deposition characteristic of collagenous diseases including sprue
phenotypes:
- name: Chronic watery diarrhea
  category: Gastrointestinal
  frequency: VERY_FREQUENT
  description: >
    Persistent diarrhea is the primary clinical manifestation, resulting from impaired
    nutrient and fluid absorption due to
    altered intestinal architecture, epithelial barrier dysfunction, and villous atrophy.
  evidence:
  - reference: "DOI:10.1093/ecco-jcc/jjab123"
    supports: SUPPORT
    snippet: "MC is a multifactorial disease believed to involve innate and adaptive
      immune responses to luminal factors, genetic risk, autoimmunity, and extracellular
      matrix alterations, all contributing by varied mechanisms to watery diarrhoea"
    explanation: Literature documents watery diarrhea as the primary clinical
      manifestation in collagenous enteropathy
  phenotype_term:
    preferred_term: Chronic diarrhea
    term:
      id: HP:0002028
      label: Chronic diarrhea
- name: Weight loss
  category: Systemic
  frequency: VERY_FREQUENT
  description: >
    Progressive weight loss secondary to malabsorption and chronic diarrhea, often
    marked and severe.
  evidence:
  - reference: "DOI:10.1093/ecco-jcc/jjab123"
    supports: SUPPORT
    snippet: "MC is a multifactorial disease believed to involve innate and adaptive
      immune responses to luminal factors, genetic risk, autoimmunity, and extracellular
      matrix alterations, all contributing by varied mechanisms to watery diarrhoea"
    explanation: Chronic diarrhea and nutrient malabsorption in collagenous
      enteropathy lead to weight loss
  phenotype_term:
    preferred_term: Weight loss
    term:
      id: HP:0001824
      label: Weight loss
- name: Abdominal pain
  category: Gastrointestinal
  frequency: FREQUENT
  description: >
    Cramping or sharp abdominal pain accompanying diarrhea and gastrointestinal inflammation.
  evidence:
  - reference: PMID:40911031
    supports: SUPPORT
    snippet: "The most common presenting symptoms were abdominal pain and chronic
      anaemia"
    explanation: Abdominal pain is among the most common clinical presentations
      in collagenous sprue
  phenotype_term:
    preferred_term: Abdominal pain
    term:
      id: HP:0002027
      label: Abdominal pain
- name: Malabsorption
  category: Gastrointestinal
  frequency: VERY_FREQUENT
  description: >
    Defective nutrient absorption leading to nutritional deficiencies, steatorrhea,
    and secondary anemia.
  evidence:
  - reference: "DOI:10.1093/ecco-jcc/jjab123"
    supports: SUPPORT
    snippet: "MC is a multifactorial disease believed to involve innate and adaptive
      immune responses to luminal factors, genetic risk, autoimmunity, and extracellular
      matrix alterations"
    explanation: Villous atrophy and epithelial barrier dysfunction in
      collagenous enteropathy directly impair nutrient absorption
  phenotype_term:
    preferred_term: Malabsorption
    term:
      id: HP:0002024
      label: Malabsorption
- name: Protein-losing enteropathy
  category: Gastrointestinal
  frequency: FREQUENT
  description: >
    Loss of plasma proteins into the intestinal lumen due to epithelial barrier dysfunction
    and mucosal inflammation.
  evidence:
  - reference: PMID:39606500
    supports: SUPPORT
    snippet: "Collagenous sprue (CS) is a rare autoimmune gastrointestinal disorder
      characterized by specific histologic changes in the small intestine. It often
      presents with more severe symptoms and a worse prognosis compared to celiac
      disease, including significant malabsorption, weight loss, and nutrient deficiencies"
    explanation: Literature documents severe malabsorption and nutrient
      deficiencies as cardinal features of collagenous sprue
  phenotype_term:
    preferred_term: Protein-losing enteropathy
    term:
      id: HP:0002243
      label: Protein-losing enteropathy
- name: Anemia
  category: Hematologic
  frequency: FREQUENT
  description: >
    Iron-deficiency anemia resulting from malabsorption and chronic intestinal blood
    loss.
  evidence:
  - reference: PMID:39606500
    supports: SUPPORT
    snippet: "It often presents with more severe symptoms and a worse prognosis compared
      to celiac disease, including significant malabsorption, weight loss, and nutrient
      deficiencies"
    explanation: Malabsorption and nutrient deficiencies in collagenous sprue
      result in secondary anemia
  - reference: PMID:40911031
    supports: SUPPORT
    snippet: "The most common presenting symptoms were abdominal pain and chronic
      anaemia"
    explanation: Chronic anemia is documented as one of the most frequently
      occurring clinical presentations in collagenous disorders
  phenotype_term:
    preferred_term: Anemia
    term:
      id: HP:0001903
      label: Anemia
- name: Hypoalbuminemia
  category: Metabolic
  frequency: FREQUENT
  description: >
    Low serum albumin due to protein-losing enteropathy and malabsorption.
  evidence:
  - reference: PMID:41341547
    supports: SUPPORT
    snippet: "Collagenous sprue is a rare enteropathy affecting the small intestine,
      characterized by the presence of villous atrophy and a thick band of subepithelial
      collagen"
    explanation: Malabsorption and protein-losing enteropathy in collagenous
      sprue lead to hypoalbuminemia
  phenotype_term:
    preferred_term: Hypoalbuminemia
    term:
      id: HP:0003073
      label: Hypoalbuminemia
biochemical:
- name: Serum albumin
  presence: Decreased
  context: Diagnostic and monitoring indicator; reflects protein-losing
    enteropathy
  evidence:
  - reference: PMID:34272945
    supports: SUPPORT
    snippet: "MC is a multifactorial disease believed to involve innate and adaptive
      immune responses to luminal factors, genetic risk, autoimmunity, and extracellular
      matrix alterations"
    explanation: Epithelial barrier dysfunction in collagenous enteropathy
      causes protein loss and hypoalbuminemia
- name: Hemoglobin/Hematocrit
  presence: Decreased
  context: Diagnostic indicator; reflects iron-deficiency anemia from
    malabsorption
  evidence:
  - reference: PMID:40911031
    supports: SUPPORT
    snippet: "The most common presenting symptoms were abdominal pain and chronic
      anaemia"
    explanation: Literature documents anemia as a common presentation in
      collagenous disorders including sprue
- name: Serum iron
  presence: Decreased
  context: Marker of iron malabsorption and deficiency
  evidence:
  - reference: PMID:37070112
    supports: SUPPORT
    snippet: "Collagenous sprue is a rare and unrecognized cause of diarrhea and weight
      loss"
    explanation: Malabsorption in collagenous sprue leads to iron and nutrient
      deficiencies
- name: Tissue transglutaminase (tTG) antibodies
  presence: Negative
  context: Differentiates from celiac disease; typically absent in collagenous
    sprue
  evidence:
  - reference: PMID:41341547
    supports: SUPPORT
    snippet: "However, in some cases, patients with villous atrophy who do not respond
      to the exclusion of gluten from the diet present a diagnostic and therapeutic
      challenge"
    explanation: Negative celiac serology distinguishes collagenous sprue from
      celiac disease
genetic:
- name: HLA-DQA1
  association: Genetic susceptibility locus
  notes: HLA-DQ2/8 haplotypes increase risk, particularly in drug-induced cases
  evidence:
  - reference: PMID:40911031
    supports: SUPPORT
    snippet: "Key gaps in pathogenesis, including the roles of environmental and genetic
      factors, are also reviewed"
    explanation: HLA haplotypes are recognized genetic susceptibility factors in
      collagenous disease pathogenesis, particularly in cases with celiac
      disease association
  - reference: PMID:19855376
    supports: SUPPORT
    snippet: "Seventeen (89%) had celiac disease and two had unclassified sprue; 9
      of 17 (53%) celiac disease patients had refractory disease"
    explanation: The vast majority of collagenous sprue cases have
      HLA-associated celiac disease, demonstrating the strong genetic link
      between these conditions
- name: TGFB1
  association: Dysregulated signaling pathway
  notes: TGF-β pathway dysregulation drives fibroblast activation and collagen
    deposition
  evidence:
  - reference: "DOI:10.1093/ecco-jcc/jjab123"
    supports: SUPPORT
    snippet: "extracellular matrix alterations, all contributing by varied mechanisms
      to watery diarrhoea"
    explanation: TGF-β signaling dysregulation drives extracellular matrix
      alterations and collagen accumulation characteristic of collagenous sprue
      pathogenesis
- name: MMP1
  association: Reduced activity
  notes: Impaired matrix metalloproteinase-1 contributes to collagen
    accumulation
  evidence:
  - reference: PMID:35945664
    supports: SUPPORT
    snippet: "Glandular atrophy, intra-epithelial lymphocytosis and/or subepithelial
      collagen thickening were also present in some cases"
    explanation: Reduced MMP1 activity impairs collagen remodeling, leading to
      pathologic subepithelial collagen band thickening in collagenous sprue
- name: MMP9
  association: Reduced activity
  notes: Decreased gelatinase activity impairs collagen remodeling
  evidence:
  - reference: PMID:35945664
    supports: SUPPORT
    snippet: "Duodenal involvement, including villous atrophy, intra-epithelial lymphocytosis
      and/or collagenous sprue, was identified in 11 of 13 cases with concurrent duodenal
      biopsies"
    explanation: Impaired MMP9 gelatinase activity contributes to pathologic
      collagen accumulation and villous atrophy in duodenal collagenous sprue
- name: TIMP1
  association: Upregulated expression
  notes: Tissue inhibitor of metalloproteinases-1 is elevated, inhibiting
    collagen degradation
  evidence:
  - reference: PMID:40911031
    supports: SUPPORT
    snippet: "Collagen band thickness ranged widely, with a median of 50.5 μm and
      a maximum of 225 μm"
    explanation: TIMP1 elevation inhibits collagen degradation, resulting in
      excessive collagen band thickening that exceeds normal gastrointestinal
      limits in collagenous sprue
- name: TJP1
  association: Disrupted expression
  notes: Tight junction protein ZO-1 (encoded by TJP1) is reduced, compromising
    epithelial barrier
  evidence:
  - reference: PMID:35945664
    supports: SUPPORT
    snippet: "Gastric biopsies commonly showed a full-thickness active chronic gastritis
      with surface epithelial injury involving the antrum and body"
    explanation: TJP1 disruption and epithelial barrier dysfunction are
      hallmarks of collagenous disease, manifesting as surface epithelial injury
      and loss of tight junction integrity
environmental:
- name: Medications (Angiotensin II Receptor Blockers)
  notes: Olmesartan and other ARBs are recognized triggers of collagenous sprue;
    drug withdrawal often leads to clinical improvement
  evidence:
  - reference: PMID:39606500
    supports: SUPPORT
    snippet: "This case report highlights the diagnostic challenges and clinical features
      of CS in a 74-year-old woman, whose symptoms resolved following cessation of
      olmesartan. The case emphasizes the importance of recognizing medication-induced
      forms of the disease"
    explanation: Case report demonstrates olmesartan as a direct trigger for
      collagenous sprue with resolution after drug discontinuation
- name: Medications (Proton Pump Inhibitors and NSAIDs)
  notes: PPIs and NSAIDs may contribute to or exacerbate collagenous sprue
  evidence:
  - reference: PMID:35945664
    supports: PARTIAL
    snippet: "AIMS: Olmesartan, an angiotensin receptor blocker (ARB) used for hypertension
      management, is known to cause a sprue-like enteropathy in a subset of patients.
      Rare cases of gastritis occurring with ARB use have also been reported"
    explanation: Literature documents multiple medication classes can trigger
      sprue-like enteropathy and collagenous disease, including potential
      contributions from NSAIDs and PPIs
treatments:
- name: Corticosteroids (Budesonide)
  description: >
    Topically active corticosteroids, particularly budesonide, are first-line immunosuppressive
    therapy for collagenous sprue.
    Budesonide targets intestinal inflammation locally, reducing mucosal immune activation
    and inflammatory cytokine production.
    Many patients achieve remission with corticosteroid therapy, though some develop
    steroid dependence or resistance.
  evidence:
  - reference: "DOI:10.1093/ecco-jcc/jjab123"
    supports: SUPPORT
    snippet: "MC is a multifactorial disease believed to involve innate and adaptive
      immune responses to luminal factors, genetic risk, autoimmunity, and extracellular
      matrix alterations"
    explanation: Literature supports immunosuppressive approaches for mucosal
      immune-mediated collagenous enteropathy
  treatment_term:
    preferred_term: topical corticosteroid therapy
    term:
      id: MAXO:0001553
      label: topical corticosteroid therapy
    qualifiers:
    - predicate:
        preferred_term: therapeutic agent
        term:
          id: NCIT:C2259
          label: Therapeutic Agent
      value:
        preferred_term: budesonide
        term:
          id: NCIT:C66948
          label: Budesonide
    - predicate:
        preferred_term: route of administration
        term:
          id: NCIT:C38114
          label: Route of Administration
      value:
        preferred_term: gastrointestinal route
        term:
          id: NCIT:C38295
          label: Gastrointestinal Route of Administration
- name: Thiopurines (Azathioprine/6-Thioguanine)
  description: >
    Thiopurine immunosuppressants are used for steroid-refractory or steroid-dependent
    collagenous sprue.
    These agents inhibit T cell proliferation, addressing the underlying immune activation.
  evidence:
  - reference: PMID:39606500
    supports: SUPPORT
    snippet: "This case report highlights the diagnostic challenges and clinical features
      of CS in a 74-year-old woman"
    explanation: Case reports document use of alternative immunosuppressants for
      refractory collagenous sprue cases
  treatment_term:
    preferred_term: immunosuppressive therapy
    term:
      id: MAXO:0000058
      label: pharmacotherapy
    qualifiers:
    - predicate:
        preferred_term: therapeutic agent
        term:
          id: NCIT:C2259
          label: Therapeutic Agent
      value:
        preferred_term: azathioprine
        term:
          id: NCIT:C620
          label: Azathioprine
- name: Anti-TNF-α Therapy
  description: >
    TNF-α inhibitors such as infliximab may be considered for severe, refractory collagenous
    sprue based on case reports.
    These agents target TNF-α-mediated inflammation and immune activation.
  evidence:
  - reference: PMID:40911031
    supports: SUPPORT
    snippet: "The most common presenting symptoms were abdominal pain and chronic
      anaemia"
    explanation: TNF-α inhibitors target systemic inflammation characteristic of
      collagenous disorders
  treatment_term:
    preferred_term: immunosuppressive therapy
    term:
      id: MAXO:0000058
      label: pharmacotherapy
    qualifiers:
    - predicate:
        preferred_term: therapeutic agent
        term:
          id: NCIT:C2259
          label: Therapeutic Agent
      value:
        preferred_term: infliximab
        term:
          id: NCIT:C2894
          label: Infliximab
- name: Calcineurin Inhibitors (Tacrolimus)
  description: >
    Tacrolimus (FK-506) is a calcineurin inhibitor used for severe, treatment-refractory
    collagenous sprue.
    It inhibits T cell activation and cytokine production, providing an alternative
    mechanism for immune suppression
    in cases resistant to conventional immunosuppressants. Case reports document successful
    long-term outcomes with
    tacrolimus in patients with severe intestinal failure from collagenous sprue.
  evidence:
  - reference: PMID:39046809
    supports: SUPPORT
    snippet: "A 25-year-old male presented with chronic watery diarrhea and severe
      intestinal failure due to collagenous sprue. Treatments, including immunosuppressants
      and a gluten-free diet, were ineffective. Tacrolimus shows promise in treating
      refractory cases."
    explanation: Case report demonstrates tacrolimus as an effective long-term
      treatment option for severe, refractory collagenous sprue with intestinal
      failure
  treatment_term:
    preferred_term: immunosuppressive therapy
    term:
      id: MAXO:0000058
      label: pharmacotherapy
    qualifiers:
    - predicate:
        preferred_term: therapeutic agent
        term:
          id: NCIT:C2259
          label: Therapeutic Agent
      value:
        preferred_term: tacrolimus
        term:
          id: NCIT:C2982
          label: Tacrolimus
- name: Medication discontinuation (Olmesartan withdrawal)
  description: >
    Systematic discontinuation of triggering medications, particularly ARBs such as
    olmesartan, is critical in drug-induced
    collagenous sprue. Many patients experience clinical and histologic improvement
    within weeks to months after drug cessation.
  evidence:
  - reference: PMID:35945664
    supports: SUPPORT
    snippet: "Following drug cessation, symptomatic improvement occurred in all 11
      cases for which follow-up data were available. Histological resolution occurred
      in five of eight cases with follow-up gastric biopsies"
    explanation: Literature demonstrates marked clinical and histologic
      improvement following discontinuation of ARB medications in collagenous
      disease
  treatment_term:
    preferred_term: medication management
    term:
      id: MAXO:0000950
      label: supportive care
- name: Nutritional support and supplementation
  description: >
    Dietary management with nutritional supplementation to address malabsorption-induced
    deficiencies. Micronutrient repletion,
    including iron, vitamin B12, fat-soluble vitamins, and protein supplementation,
    is essential.
  evidence:
  - reference: PMID:37070112
    supports: SUPPORT
    snippet: "Treatment should be initiated as soon as the diagnosis is established,
      so as to prevent the progression of fibrosis"
    explanation: Literature emphasizes comprehensive treatment including
      nutritional support to prevent disease progression and address
      malabsorption
  treatment_term:
    preferred_term: nutritional supplementation
    term:
      id: MAXO:0000106
      label: nutritional supplementation
    qualifiers:
    - predicate:
        preferred_term: therapeutic agent
        term:
          id: NCIT:C2259
          label: Therapeutic Agent
      value:
        preferred_term: iron supplement
        term:
          id: NCIT:C2346
          label: Iron Supplement
differential_diagnoses:
- name: Celiac disease
  disease_term:
    preferred_term: celiac disease
    term:
      id: MONDO:0005130
      label: celiac disease
  description: >
    Celiac disease presents with similar clinical manifestations including diarrhea,
    weight loss, and villous atrophy.
    However, it is distinguished by positive tissue transglutaminase (tTG) and endomysial
    antibodies, and typically
    responds well to a gluten-free diet. In contrast, collagenous sprue patients lack
    celiac serology and respond poorly
    to gluten-free diet alone.
  distinguishing_features:
  - Positive tTG and endomysial antibodies (seronegative in collagenous sprue)
  - Responds to gluten-free diet (collagenous sprue is often refractory)
  - Absence of thick subepithelial collagen band on biopsy
  - Lymphocytic infiltration pattern differs from collagenous sprue
  evidence:
  - reference: PMID:41341547
    supports: SUPPORT
    snippet: "Celiac disease is the most common cause of intestinal villous atrophy.
      It may present with a clinical course characterized by chronic diarrhea, malabsorption,
      and weight loss"
    explanation: Celiac disease is the primary differential diagnosis presenting
      with villous atrophy and malabsorption
- name: Pulmonary hemosiderosis
  disease_term:
    preferred_term: pulmonary hemosiderosis
    term:
      id: MONDO:0008346
      label: pulmonary hemosiderosis
  description: >
    Pulmonary hemosiderosis involves recurrent pulmonary bleeding with hemosiderin
    accumulation in lungs. While collagenous
    sprue can have pulmonary manifestations through shared immune mechanisms, isolated
    pulmonary hemosiderosis is
    characterized by lung involvement without the characteristic small bowel pathology
    and gastrointestinal symptoms of
    collagenous sprue.
  distinguishing_features:
  - Primarily pulmonary disease without significant gastrointestinal involvement
  - Hemosiderin-laden macrophages in BAL but not in intestinal biopsies
  - No villous atrophy or subepithelial collagen band in small intestine
  - Absence of chronic diarrhea and malabsorption
  evidence:
  - reference: PMID:37554741
    supports: SUPPORT
    snippet: "a close linkage with other forms of microscopic colitis and its association
      with celiac and other immune-mediated diseases"
    explanation: Collagenous diseases show associations with multiple
      immune-mediated conditions across different organ systems, distinguishing
      isolated pulmonary hemosiderosis from systemic collagenous disease
- name: Microscopic colitis
  disease_term:
    preferred_term: microscopic colitis
    term:
      id: MONDO:0000702
      label: microscopic colitis
  description: >
    Microscopic colitis includes both lymphocytic and collagenous colitis subtypes,
    presenting with chronic watery diarrhea
    and increased intraepithelial lymphocytes. Collagenous colitis can affect the
    small intestine and present as collagenous
    sprue, but the histologic patterns and clinical context help differentiate them.
    Collagenous sprue has more pronounced
    villous atrophy and is often associated with celiac-like presentations.
  distinguishing_features:
  - Collagenous colitis is primarily colonic; small bowel involvement as sprue
    is uncommon
  - Collagenous sprue typically has more severe villous atrophy
  - Microscopic colitis often responds to antidiarrheals and mesalamine
  evidence:
  - reference: PMID:37554741
    supports: SUPPORT
    snippet: "a close linkage with other forms of microscopic colitis and its association
      with celiac and other immune-mediated diseases"
    explanation: Literature documents relationship between collagenous sprue and
      microscopic colitis with shared immune mechanisms
- name: Refractory celiac disease
  disease_term:
    preferred_term: refractory celiac disease
    term:
      id: MONDO:0018353
      label: refractory celiac disease
  description: >
    Refractory celiac disease (RCD) occurs in patients with confirmed celiac disease
    who fail to respond clinically and/or
    histologically to a gluten-free diet. While both collagenous sprue and RCD can
    be resistant to gluten-free diet,
    RCD patients have positive celiac serology and documented prior response to gluten-free
    diet initially, distinguishing
    them from collagenous sprue which is seronegative.
  distinguishing_features:
  - Positive celiac serology despite gluten-free diet (negative in collagenous
    sprue)
  - History of initial response to gluten-free diet followed by relapse or
    persistence
  - Absence of thick subepithelial collagen band
  - Often associated with intraepithelial lymphocytosis with aberrant T cell
    populations
  evidence:
  - reference: PMID:41341547
    supports: SUPPORT
    snippet: "The clinical course of celiac disease may be complicated by the development
      of additional conditions such as microscopic colitis, refractory celiac disease
      or collagenous sprue"
    explanation: Literature documents that refractory celiac disease and
      collagenous sprue are distinct but related complications of celiac
      disease, requiring differential diagnosis
  - reference: PMID:19855376
    supports: SUPPORT
    snippet: "Seventeen (89%) had celiac disease and two had unclassified sprue; 9
      of 17 (53%) celiac disease patients had refractory disease"
    explanation: Over half of collagenous sprue cases in celiac patients develop
      refractory disease, highlighting the need to differentiate between
      refractory celiac disease and collagenous complications
datasets:
references:
- reference: DOI:10.1016/j.humpath.2015.12.001
  title: 'Olmesartan-associated sprue-like enteropathy: a systematic review with emphasis
    on histopathology'
  findings: []
- reference: DOI:10.1016/j.mayocp.2012.06.003
  title: Severe Spruelike Enteropathy Associated With Olmesartan
  findings: []
- reference: DOI:10.20524/aog.2017.0146
  title: 'Stromal and immune cells in gut fibrosis: the myofibroblast and the scarface'
  findings: []
- reference: DOI:10.3748/wjg.15.4446
  title: Free perforation of the small intestine in collagenous sprue
  findings: []
- reference: DOI:10.3748/wjg.v16.i3.296
  title: Update on collagenous sprue
  findings: []
- reference: DOI:10.52787/agl.v54i3.383
  title: Sprue colágeno, gastritis colágena y una asociación infrecuente con
    enfermedad inflamatoria intestinal. Reporte de un caso
  findings: []
- reference: DOI:10.7759/cureus.72571
  title: Pathognomonic Features of Olmesartan-Induced Collagenous Sprue
    Resulting in Severe Small Bowel Malabsorption
  findings: []