Toxinogene Corynebacterium diphtheriae-surinfectie van een chronisch ulcus

Toxigenic Corynebacterium diphtheriae superinfection of a chronic ulcer This article describes the medical history of a 92-year-old Congolese woman with a chronic ulcer on the right inner ankle, present since childhood after scratching small bumps. After returning from a holiday in Congo, the patient had a swollen right lower leg and the ulcer had become remarkably painful. Corynebacterium diphtheriae was cultured from a wound culture and toxin production was demonstrated by a PCR and an immunoprecipitation test (Elek test). Cutaneous diphtheria, usually caused by C. diphtheriae or C. ulcerans, has been on the rise in recent years, primarily due to frequent travelling to endemic areas and migration. The patient was initially treated with azithromycin for 2 weeks, whereafter a control culture showed no evidence of C. diphtheriae. Given the persistent pain symptoms, azithromycin was continued for 2 more weeks. The patient had received only 1 documented vaccine and was thus incompletely vaccinated against diphtheria. A nasopharyngeal carrier status could not be demonstrated. Contact isolation is strongly recommended in patients with toxigenic skin diphtheria since they form a reservoir for secondary transmission with the risk of respiratory diphtheria. Unprotected contacts with the wound exudate should be treated prophylactically with azithromycin 500 mg once a day for 3 days or a single intramuscular administration of 1.2 million units of benzathine-penicillin. Despite large-scale vaccination programs against diphtheria, a physician should include cutaneous diphtheria in the differential diagnosis in case of a non-healing ulcer with a grayish attachment.