Acute schistosomiasis — Katayama fever — presents in immunologically naïve patients (typically travellers) with fever, dry cough, fatigue, headache, myalgia, arthralgia, abdominal pain, and diarrhoea, accompanied by prominent eosinophilia. This syndrome does not typically occur in individuals from endemic regions.
Katayama fever is an immune-mediated, serum sickness–like hypersensitivity reaction driven by migrating and maturing schistosomulae. Because the reaction depends on immunological naivety, a careful travel and exposure history is central to diagnosis. Rare presentations include periorbital oedema, urticaria, encephalitis, and myocarditis.
Management addresses both the acute immune-mediated reaction and the underlying parasitic infection through a structured, phased approach — beginning with an agent to suppress the hypersensitivity response, with antiparasitic therapy introduced at a specific point in the course. Treatment continues into a distinct subsequent phase once the infection has progressed. The complete protocol, including agent selection, timing, sequencing, and all individualised considerations, is available via the link below.