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This is a clinician-written, evidence-based summary aligned to the 2026 MLA Content Map. It is intended for medical students and junior doctors preparing for the UKMLA. Always cross-reference with NICE guidance, local protocols, and clinical judgement.
The Bottom Line
- Multisystem granulomatous disease — NON-CASEATING granulomata (distinguishes from TB which caseates)
- Classic CXR: bilateral hilar lymphadenopathy (BHL) ± pulmonary infiltrates — staging I–IV
- Löfgren syndrome (acute sarcoidosis): BHL + erythema nodosum + polyarthralgia + fever — excellent prognosis
- Raised serum ACE (produced by granulomata) — non-specific but supports diagnosis
- Treatment: most cases self-resolve; oral prednisolone for progressive pulmonary disease, hypercalcaemia, or end-organ damage
Overview
Sarcoidosis is a systemic granulomatous disease of unknown aetiology characterised by the formation of non-caseating epithelioid granulomata in affected organs. The lungs and intrathoracic lymph nodes are involved in >90% of cases. Other commonly affected organs include the skin (erythema nodosum, lupus pernio), eyes (anterior uveitis), liver, joints, and heart. The disease is staged radiographically: stage 0 (normal CXR), stage I (BHL alone), stage II (BHL + pulmonary infiltrates), stage III (pulmonary infiltrates without BHL), stage IV (pulmonary fibrosis). Most patients with stage I disease have spontaneous remission (~80%).
Epidemiology
UK incidence is approximately 5 per 100,000. It is most common in adults aged 25–40. There is a higher prevalence in people of African-Caribbean descent (3–4 times higher than in white Europeans), and in this group, disease tends to be more severe and chronic. Women are slightly more affected. The condition is more common in non-smokers (an unusual pattern for respiratory diseases). Löfgren syndrome is more common in Scandinavians and Northern Europeans.
Clinical Features
Symptoms
Dry cough and progressive breathlessness
Fatigue — often debilitating and out of proportion to lung involvement
Erythema nodosum — painful red nodules on shins (Löfgren syndrome)
Joint pain (especially ankles)
Blurred vision or red eye (anterior uveitis)
Skin lesions: lupus pernio (violaceous plaques on nose, cheeks, ears)
Fever, weight loss, night sweats (may mimic TB or lymphoma)
Signs
Bilateral hilar lymphadenopathy on CXR (hallmark)
Erythema nodosum (tender subcutaneous nodules on shins)
Hepatosplenomegaly
Parotid gland enlargement (Heerfordt syndrome: parotitis + uveitis + facial nerve palsy + fever)
Peripheral lymphadenopathy
Lupus pernio (chronic skin sarcoidosis)
Investigations
First-line
Chest X-rayBilateral hilar lymphadenopathy ± pulmonary infiltrates — stage disease I–IV
Serum ACE (angiotensin-converting enzyme)Raised in ~60% of active sarcoidosis (produced by granulomata) — non-specific, also raised in TB, lymphoma
Serum calciumHypercalcaemia in ~10% (macrophages in granulomata convert 25-OH vitamin D to active 1,25-OH vitamin D) — can cause renal stones
SpirometryRestrictive pattern (reduced FVC with normal/raised FEV1/FVC ratio) or may be obstructive if endobronchial involvement
Second-line
CT thoraxBetter assessment of parenchymal disease, lymphadenopathy, and fibrosis
TLCO (transfer factor)Reduced in pulmonary sarcoidosis — useful for monitoring disease activity
Liver function testsRaised ALP suggests hepatic granulomata
24-hour urine calciumIf hypercalcaemia or renal stones — increased calcium excretion
Specialist
Tissue biopsyDefinitive diagnosis — non-caseating granulomata on histology. Common sites: transbronchial biopsy, skin lesion, lymph node
ECG and cardiac MRIScreen for cardiac sarcoidosis — can cause arrhythmias, conduction block, cardiomyopathy
Ophthalmology reviewSlit-lamp examination for anterior uveitis — can be asymptomatic
1
Observation (stage I or asymptomatic)
- Most stage I disease self-resolves within 2 years (~80%)
- Löfgren syndrome has an excellent prognosis — NSAIDs for joint pain, usually self-limiting
- Monitor with serial CXR, spirometry, and serum ACE
2
Corticosteroid treatment (progressive or end-organ disease)
- Oral prednisolone 0.5 mg/kg/day (typically 20–40 mg) for 4–6 weeks, then taper over 6–12 months
- Indications: progressive pulmonary disease (declining FVC/TLCO), hypercalcaemia, cardiac sarcoidosis, neurosarcoidosis, sight-threatening uveitis
- Bone protection (calcium, vitamin D, bisphosphonate) for prolonged steroid courses
3
Steroid-sparing agents (refractory or relapsing)
- Methotrexate, azathioprine, or mycophenolate
- Anti-TNF therapy (infliximab) for severe refractory disease
Complications
- Pulmonary fibrosis: Stage IV — irreversible, may require transplant assessment
- Hypercalcaemia and renal stones: From excessive 1,25-dihydroxyvitamin D production
- Cardiac sarcoidosis: Heart block, VT, cardiomyopathy — potentially fatal
- Neurosarcoidosis: Cranial nerve palsies (especially VII), aseptic meningitis, hypothalamic dysfunction
- Anterior uveitis: Can cause vision loss if untreated
UKMLA Exam Tips
- 1Bilateral hilar lymphadenopathy + erythema nodosum + polyarthralgia = Löfgren syndrome (acute sarcoidosis) — excellent prognosis
- 2NON-CASEATING granulomata = sarcoidosis. CASEATING granulomata = TB
- 3Serum ACE is raised in sarcoidosis but is NOT specific — TB and lymphoma can also raise it
- 4Hypercalcaemia in sarcoidosis = macrophages producing 1,25-dihydroxyvitamin D (1-alpha-hydroxylase activity)
- 5Lupus pernio = chronic cutaneous sarcoidosis on the face — poor prognostic marker
- 6Always screen for cardiac and ocular involvement — can be asymptomatic but serious
- 7BHL on CXR DDx: sarcoidosis, lymphoma, TB — but bilateral SYMMETRICAL BHL strongly suggests sarcoidosis
practicetest your knowledge on sarcoidosisApply what you've learnt with UKMLA-style questions from the iatroX Q-Bank — respiratory and beyond.
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