Adult-Onset Still's Disease

Diagnosis (≥5 with ≥2 major): Major: fever ≥39°C >1 week (quotidian — daily spikes); arthralgia / arthritis ≥2 weeks; salmon-pink evanescent rash; leukocytosis ≥10 with ≥80% neutrophils. Minor: sore throat; lymphadenopathy / hepatosplenomegaly; abnormal LFTs; negative RF + ANA. Exclude: infection (especially viral, TB, endocarditis), malignancy (especially lymphoma, leukaemia), other autoimmune, Behçet's, drug reaction. Ferritin often massively raised (>1000–10,000) — glycosylated ferritin <20% supportive but not diagnostic.