Sarcoidosis is a multisystem inflammatory disease of unknown etiology characterized by the formation of non-caseating granulomas, most commonly affecting the lungs and lymph nodes. It predominantly affects adults aged 20-40 years, with higher incidence in African Americans and Northern Europeans. Clinical presentation ranges from asymptomatic to severe organ dysfunction. While many cases resolve spontaneously, chronic progressive disease occurs in a significant subset.
name: Sarcoidosis
creation_date: '2026-01-13T07:11:10Z'
updated_date: '2026-03-27T19:10:00Z'
category: Immune
description: >
Sarcoidosis is a multisystem inflammatory disease of unknown etiology characterized
by the formation of non-caseating granulomas, most commonly affecting the lungs
and lymph nodes. It predominantly affects adults aged 20-40 years, with higher
incidence in African Americans and Northern Europeans. Clinical presentation
ranges from asymptomatic to severe organ dysfunction. While many cases resolve
spontaneously, chronic progressive disease occurs in a significant subset.
disease_term:
preferred_term: sarcoidosis
term:
id: MONDO:0019338
label: sarcoidosis
parents:
- Granulomatous Disease
- Immune-Mediated Disease
has_subtypes:
- name: Pulmonary Sarcoidosis
description: Most common form, affecting lungs and hilar lymph nodes; staged by chest radiograph findings.
- name: Cardiac Sarcoidosis
description: Myocardial granulomas causing conduction abnormalities, heart failure, or sudden death.
- name: Neurosarcoidosis
description: CNS involvement causing cranial neuropathies, meningitis, or mass lesions.
- name: Cutaneous Sarcoidosis
description: Skin manifestations including erythema nodosum, lupus pernio, and papular lesions.
pathophysiology:
- name: Granuloma Formation
description: >
Non-caseating granulomas consist of organized collections of activated
macrophages (epithelioid cells), multinucleated giant cells, and CD4+ T cells.
Th1/Th17 immune responses drive granuloma development in response to
unidentified antigens.
evidence:
- reference: PMID:35011621
supports: PARTIAL
evidence_source: HUMAN_CLINICAL
snippet: "Sarcoidosis is a chameleon disease of unknown etiology, characterized by the growth of non-necrotizing and non-caseating granulomas"
explanation: "This review confirms the characteristic non-caseating granuloma formation in sarcoidosis."
cell_types:
- preferred_term: epithelioid macrophage
term:
id: CL:0002150
label: epithelioid macrophage
- preferred_term: CD4-positive helper T cell
term:
id: CL:0000492
label: CD4-positive helper T cell
biological_processes:
- preferred_term: granuloma formation
term:
id: GO:0002432
label: granuloma formation
- name: Dysregulated Immune Response
description: >
Altered CD4+ T-cell subset balance, including increased IFN-gamma-positive
Th17 cells and dysfunctional regulatory T-cell survival, contributes to
persistent inflammation in sarcoidosis.
evidence:
- reference: PMID:24882950
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "The proportion of Th17 cells positive for IFN-gamma was greater in sarcoidosis than controls (median 72.4% versus 31%, P = 0.0005) and increased with radiologic stage (N = 23, rho = 0.45, and P = 0.03)."
explanation: This study directly supports enrichment of IFN-gamma-positive Th17 cells and a dysregulated effector T-cell compartment in sarcoidosis.
- reference: PMID:26376720
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "In untreated patients with active pulmonary sarcoidosis, Tregs show impaired survival and enhanced apoptotic susceptibility towards CD95L. Increased apoptosis likely contributes to the insufficient immunosuppressive function of sarcoidosis Tregs."
explanation: This study directly supports impaired regulatory T-cell survival and function as a contributor to ongoing sarcoid inflammation.
cell_types:
- preferred_term: CD4-positive helper T cell
term:
id: CL:0000492
label: CD4-positive helper T cell
biological_processes:
- preferred_term: inflammatory response
term:
id: GO:0006954
label: inflammatory response
- name: Fibrosis
description: >
Chronic granulomatous inflammation can progress to pulmonary fibrocystic
change and fibrosis, leading to irreversible organ damage and functional
impairment.
evidence:
- reference: PMID:41095908
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Although many patients experience spontaneous remission, approximately 10-30% develop progressive pulmonary disease, which may lead to fibrocystic changes, respiratory failure, and death."
explanation: This review directly supports progression from pulmonary sarcoidosis to fibrocystic and fibrotic lung disease in a substantial subset of patients.
phenotypes:
- name: Mediastinal Lymphadenopathy
category: Pulmonary
frequency: VERY_FREQUENT
description: Symmetric enlargement of hilar and mediastinal lymph nodes, often the presenting finding on chest radiograph.
phenotype_term:
preferred_term: Mediastinal lymphadenopathy
term:
id: HP:0100721
label: Mediastinal lymphadenopathy
evidence:
- reference: PMID:31485575
supports: PARTIAL
evidence_source: HUMAN_CLINICAL
snippet: "Although intrathoracic involvement is the hallmark of the disease, present
in over 90% of patients, sarcoidosis can affect virtually any organ."
explanation: This Mayo Clinic review strongly supports intrathoracic involvement as the dominant manifestation of sarcoidosis, but only indirectly supports mediastinal lymphadenopathy specifically.
- name: Dyspnea
category: Pulmonary
frequency: FREQUENT
description: Shortness of breath due to pulmonary involvement and reduced lung function.
phenotype_term:
preferred_term: Dyspnea
term:
id: HP:0002094
label: Dyspnea
evidence:
- reference: PMID:38227868
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Ongoing dyspnea and dry cough in a young to middle-aged adult should
increase the suspicion for sarcoidosis."
explanation: This 2024 American Family Physician review identifies dyspnea as
a key presenting symptom that should raise suspicion for sarcoidosis.
- name: Nonproductive Cough
category: Pulmonary
frequency: FREQUENT
description: Dry, non-productive cough from airway and parenchymal inflammation.
phenotype_term:
preferred_term: Nonproductive cough
term:
id: HP:0031246
label: Nonproductive cough
evidence:
- reference: PMID:38227868
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Ongoing dyspnea and dry cough in a young to middle-aged adult should
increase the suspicion for sarcoidosis."
explanation: Dry cough is identified as a hallmark symptom that should raise
clinical suspicion for sarcoidosis in younger adults.
- name: Fatigue
category: Constitutional
frequency: FREQUENT
description: Chronic fatigue is one of the most debilitating symptoms, often persisting after disease resolution.
phenotype_term:
preferred_term: Fatigue
term:
id: HP:0012378
label: Fatigue
evidence:
- reference: PMID:38227868
supports: PARTIAL
evidence_source: HUMAN_CLINICAL
snippet: "Patients with sarcoidosis can exhibit constitutional symptoms such as
fever, unintentional weight loss, and fatigue."
explanation: This review supports fatigue as a recognized constitutional symptom in sarcoidosis, but the wording is not strong enough on its own to justify a VERY_FREQUENT frequency assignment.
- name: Erythema Nodosum
category: Dermatologic
frequency: OCCASIONAL
description: Painful red nodules on the shins, often associated with acute sarcoidosis (Lofgren syndrome).
phenotype_term:
preferred_term: Erythema nodosum
term:
id: HP:0012219
label: Erythema nodosum
evidence:
- reference: PMID:39082153
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Löfgren syndrome (LS) is a sarcoidosis subtype characterised by an acute disease course, bilateral hilar lymphadenopathy (BHL), erythema nodosum (EN), and ankle arthritis."
explanation: This review of Lofgren syndrome directly supports erythema nodosum as a recognized acute cutaneous manifestation of sarcoidosis.
- name: Uveitis
category: Ophthalmologic
frequency: OCCASIONAL
description: Eye inflammation that can lead to vision impairment if untreated. May be anterior, posterior, or panuveitis.
phenotype_term:
preferred_term: Uveitis
term:
id: HP:0000554
label: Uveitis
evidence:
- reference: PMID:33173272
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Uveitis was the most common ocular manifestation."
explanation: This retrospective series directly supports uveitis as a common ocular manifestation among patients with ocular sarcoidosis.
biochemical:
- name: Elevated ACE
presence: Elevated
context: Serum angiotensin-converting enzyme often elevated but not specific for diagnosis
evidence:
- reference: PMID:36778180
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Raised angiotensin-converting enzyme (ACE) levels were found in 56.8% of patients."
explanation: This retrospective cohort directly supports frequent elevation of serum ACE in sarcoidosis while remaining compatible with its limited diagnostic specificity.
- name: Hypercalcemia
presence: Elevated
context: Due to ectopic 1,25-dihydroxyvitamin D (calcitriol) production by granuloma macrophages
evidence:
- reference: PMID:24663253
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Hypercalcemia in sarcoidosis is due to three mechanistic reasons: (1) systemic conversion of 25-hydroxyvitamin D to 1,25-dihydroxyvitamin D by the enzyme 1-alpha hydroxylase produced by activated monocyte/macrophage system, (2) production of parathormone-related peptide (PTHrP) by the sarcoid granuloma, (3) tissue-level conversion of 25-hydroxyvitamin D to 1,25-dihydroxyvitamin D by 1-alphahydroxylase produced by local monocyte/macrophage system in the sarcoid granuloma."
explanation: This case-based report explicitly supports hypercalcemia in sarcoidosis and ties it to macrophage-driven calcitriol dysregulation within granulomatous tissue.
- name: Elevated Inflammatory Markers
presence: Elevated
context: ESR and CRP may be elevated during active disease
evidence:
- reference: PMID:32407763
supports: PARTIAL
evidence_source: HUMAN_CLINICAL
snippet: "In contrast, ESR and Hs-CRP emerges to be more sensitive markers of active CS."
explanation: This study directly supports ESR and CRP elevation in active cardiac sarcoidosis, partially supporting their broader use as inflammatory activity markers in sarcoidosis.
genetic:
- name: HLA-DRB1 Variants
association: Susceptibility
notes: HLA-DRB1 alleles are associated with susceptibility and disease course; DRB1*03 has been linked to resolving disease in some populations.
evidence:
- reference: PMID:25506722
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "This study has identified DRB1*03:01 and *03:02 as novel alleles associated with disease susceptibility and course in African Americans."
explanation: This large genetic association study directly supports HLA-DRB1 variation as a determinant of sarcoidosis susceptibility and clinical course.
- name: BTNL2 Variants
association: Susceptibility
notes: BTNL2 rs2076530 A-allele variation is associated with increased sarcoidosis risk.
evidence:
- reference: PMID:21410903
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "The BTNL2 A allele variant occurs with a high frequency in Danish patients with sarcoidosis and the AA genotype is associated with a ~threefold higher risk of sarcoidosis than the GG genotype."
explanation: This case-control study directly supports BTNL2 variation as a sarcoidosis susceptibility factor.
environmental:
- name: Occupational Exposures
notes: Associations have been reported with silica, other inorganic dusts, metals, and related occupational dust exposures.
evidence:
- reference: PMID:35156713
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Occupational exposures for which associations are strongest and most consistent are silica and other inorganic dusts, World Trade Center (WTC) dust, and metals."
explanation: This occupational case series review directly supports industrial dust and metal exposure as relevant environmental associations in sarcoidosis.
- name: Infectious Triggers
notes: Mycobacterial and propionibacterial antigens have been implicated as potential triggers
evidence:
- reference: PMID:22596102
supports: SUPPORT
evidence_source: OTHER
snippet: "Mycobacterial and propionibacterial organisms are the most commonly implicated potential etiologic agents."
explanation: This pathology study directly supports mycobacterial and propionibacterial organisms as leading infectious candidates in sarcoidosis pathogenesis.
treatments:
- name: Corticosteroid Therapy
description: >
First-line treatment for symptomatic sarcoidosis. Prednisone typically
initiated at 20-40mg daily with gradual taper over months. Effective
for most organ manifestations.
treatment_term:
preferred_term: corticosteroid agent therapy
term:
id: MAXO:0000640
label: corticosteroid agent therapy
evidence:
- reference: PMID:31485575
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Glucocorticoids are the cornerstone of treatment of sarcoidosis even
though evidence from randomized controlled studies is lacking."
explanation: This Mayo Clinic review establishes glucocorticoids as the cornerstone
of sarcoidosis treatment.
- reference: PMID:38227868
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Corticosteroids are the initial treatment for active disease, with
refractory cases often requiring immunosuppressive or biologic therapies."
explanation: This 2024 review confirms corticosteroids as first-line initial
treatment for active sarcoidosis.
- name: Methotrexate
description: >
Most commonly used steroid-sparing agent for chronic sarcoidosis.
Allows reduction of corticosteroid dose while maintaining disease control.
treatment_term:
preferred_term: pharmacotherapy
term:
id: MAXO:0000058
label: pharmacotherapy
therapeutic_agent:
- preferred_term: methotrexate
term:
id: CHEBI:44185
label: methotrexate
evidence:
- reference: PMID:41095908
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Antimetabolites such as methotrexate, azathioprine, mycophenolate mofetil, and leflunomide are commonly used second-line therapies."
explanation: This evidence-based review directly supports methotrexate as a standard second-line steroid-sparing therapy in pulmonary sarcoidosis.
- name: Anti-TNF Therapy
description: >
Anti-TNF agents, particularly infliximab, are used for refractory
sarcoidosis when corticosteroids and steroid-sparing agents are
insufficient.
treatment_term:
preferred_term: pharmacotherapy
term:
id: MAXO:0000058
label: pharmacotherapy
evidence:
- reference: PMID:41095908
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "For refractory disease, particularly in those with metabolically active lesions on FDG-PET, anti-tumor necrosis factor (TNF) agents like infliximab may be effective but carry risks of serious adverse effects."
explanation: This evidence-based review directly supports anti-TNF therapy, especially infliximab, as an option for refractory sarcoidosis.
datasets: