Eschar: An Important Visual Diagnosis in a Returning Traveler

[摘要] A 45-year-old man complained of fever, headache, and muscle pains a week after returning from a safari in South Africa. Clinical examination revealed a fine rash on the torso and a characteristic skin lesion on the big toe. This necrotic lesion surrounded by reddening develops into a prominent scab over the course of time and is known as eschar or „tache noire“ (French for “black spot”). The lesion is typically found at the site of a bite from a rickettsia-transmitting arthropod. In this case the patient was suffering from African tick-bite fever caused by Rickettsia africae . Rickettsiosis is a type of anthropozoonosis that occurs worldwide. R. conorii , the agent of Mediterranean spotted fever, is widespread in southern Europe. Various rickettsiae, e.g., R. felis , are endemic in Germany. The clinical triad of fever, rash, and eschar is a clear pointer to the diagnosis, although the eschar may be absent. Laboratory tests, showing a normal blood count or sometimes leukopenia or thrombocytopenia, yield no clear signs of a bacterial infection. Typically, specific antibodies were first demonstrated 3 weeks later. Because rickettsiosis can develop into a severe illness, doxycycline is indicated immediately after the initial visual diagnosis.

[学科分类] 医学（综合）