A 20-year-old female patient with the typical signs of Wissler's subsepsis allergica (Wissler-Fanconi syndrome) is described. This rare disease is characterized by four typical symptoms: polymorphous exanthemas, recurrent high fever, leucocytosis and arthralgia. In the early stages it is difficult to differentiate from septicaemia. This syndrome has sometimes been considered equivalent to or an initial stage of Still's disease (juvenile rheumatoid arthritis) progressing to degenerative arthritis in many patients, whereas other authors have classified it as a separate entity with good prognosis. The present case demonstrates that Wissler's subsepsis allergica should be considered when ever transient polymorphous exanthema is accompanied by high recurrent fever, leucocytosis and arthralgia.