'Trap' the diagnosis: a man with recurrent episodes of febrile peritonitis, not just familial Mediterranean fever

Monogenic periodic fever syndromes are characterized by recurrent episodes of fever, accompanied by localized inflammatory manifestations. Among them, familial Mediterranean fever (FMF) is the most studied and is by far the most prevalent periodic fever syndrome in Israel. We present a diagnostic workup of a patient suffering from a periodic fever syndrome, initially thought to be FMF and characterized by attacks of fever, severe abdominal pain, a migratory erythematous rash and conjunctivitis. The development of periorbital edema presenting as diplopia led to consideration of tumor necrosis factor receptor-1-associated periodic syndrome (TRAPS). Genetic tests confirmed the diagnosis. This case should alert us that even in Israel, a patient with periodic fever not fully consistent with the typical features of FMF, should be evaluated for other periodic fever syndromes.