[Disseminated actinomycosis treated with clindamycin]

Actinomycosis is a rare bacterial disease caused by Actinomyces spp., an anaerobic bacteria from the oropharynx, digestive, and female genital tracts. Initial clinical presentation often mimics malignancy, which can lead to a delay in diagnosis. Cervico-facial, genitourinary, digestive, and respiratory features are the most frequent. Few cases are reported in children and risk factors are not well known in this population. We report on the case of an 8-year-old boy with disseminated actinomycosis with cervico-facial, pulmonary, and bone involvement caused by Actinomyces israelii. The infiltrative appearance initially suggested malignancy and the patient was started on chemotherapy for presumed histiocytosis. Evaluation of subsequent tissue samples demonstrated the presence of filamentous structures consistent with fungal or filamentous bacterial infection. Prolonged culture yielded the correct diagnosis. The patient had a severe allergic reaction to piperacillin/tazobactam and was therefore transitioned to clindamycin to complete a 9-month course. This treatment, which has not been reported in children, led to a favorable clinical, biological, and radiological response, with a good clinical tolerance.