Spotless boutonneuse fever.

Mediterranean spotted fever is endemic in southern France, especially during summer. Clinical diagnosis is generally based upon the presence of a febrile eruption with or without the typical tache noire. Usual laboratory findings, which include thrombocytopenia, elevated levels of hepatic enzymes, and hyponatremia, are not specific to the disease. The diagnosis may be confirmed serologically by obtaining specific western immunoblot results and by isolation of Rickettsia conorii from blood culture with use of the shell vial cell culture technique. We report here the first documented case of spotless boutonneuse fever.