Clostridium septicum myonecrosis in a pediatric patient with a self-reported penicillin allergy

Infections with Clostridium septicum are especially rare in pediatric patients. C. septicum is the most common cause of spontaneous myonecrosis and is usually associated with comorbid malignancy. Treatment of choice for cases of C. septicum myonecrosis is prompt and thorough surgical debridement and antimicrobial therapy with high dose penicillin. The experience and management of C. septicum infections in patients who are unable to take penicillin are not well described, and the optimal duration of therapy is largely unknown. We describe a case of spontaneous myonecrosis in a 14-year-old receiving cytotoxic chemotherapy for Burkitt's lymphoma who had an anecdotal history of a penicillin allergy. Her infection was initially treated with ceftazidime and metronidazole in concert with debridement but was ultimately cured with 3 weeks of intravenous penicillin therapy following a graded penicillin challenge in hospital. We observed a delayed inflammatory tissue response to a C. septicum skin, soft tissue infection that temporally corresponded to neutrophil reconstitution in our patient with severe neutropenia. Our experience demonstrates that C. septicum myonecrosis can present indolently and progress rapidly and highlights the need for clinical vigilance and repeat "second-look" surgeries. Our case also emphasizes the importance of de-labelling penicillin allergies.