Multi-system disease characterised by granuloma formation (type IV reaction) to an unknown antigen, resulting in widespread inflammatory changes and complications
Aetiology
Unknown aetiology
May occur at any age but is usually seen in adults under the age of 50 years
Occurs more frequently in Afro-Caribbean patients, who are also more likely to develop extrapulmonary or chronic disease
Higher incidence in females
Pathophysiology
Inhalation of unknown antigen stimulates alveolar macrophages, CD4+ T cells, CD8+ T cells and B cells
Failure to clear antigen → persistent stimulation and granuloma formation → tissue damage and fibrosis
Clinical features
Typically presents with bilateral hilar lymphadenopathy, pulmonary infiltration and skin or eye lesions
Up to 50% of patients are asymptomatic and were diagnosed on the basis of routine CXR
Symptoms
Constitutional - fever, weight loss, fatigue
Respiratory - cough, dyspnoea, wheeze, chest pain
Wide range of other non-pulmonary signs e.g. hepatomegaly, splenomegaly, uveitis, erythema nodosum, skin infiltration