24th February 2025

Signs and symptoms of AOSD

The clinical features are varied and often non-specific, making the diagnosis a challenge and so requiring a low index of suspicion:

• Fever – sudden-onset daily fevers up to 40℃, typically in the late afternoon/early evening, which settle without antipyretics in a majority of cases. Fever is the most common first symptom.
• Rash – typically a salmon-pink macular or maculopapular rash of the trunk and limbs, appearing whilst febrile and then disappearing. This occurs in around 70% of cases.
• Arthritis – classically mild, oligoarticular and transient but may evolve into a severe, symmetrical polyarthropathy. The wrists, knees and ankles are mainly affected, but the shoulders, elbows, hands and hips may also be involved.
• Pharyngitis – occurs in approximately 70% of cases, particularly if an infective trigger is thought likely.
• Hepatomegaly, splenomegaly and/or lymphadenopathy – occurs in approximately 50% of cases.
• Serositis – in approximately one-third of cases, pleuritis and pericarditis occur, their signs and symptoms adding to the confusing constellations of clinical features possible at presentation.

AOSD has considerable overlap with many other conditions, some of which also have multi-system manifestations, and so, in a similar manner to JIA, AOSD is a diagnosis of exclusion.