Actinomycosis of the Forearm: An Unusual Presentation of an Early Event.

Actinomycosis is a rare chronic infectious disease, most commonly affecting the cervicofacial, pulmonary, or genitourinary areas. It is caused by the Actinomyces spp. bacteria, which are facultative anaerobes and gram-positive, nonsporing rods. The disease is characterized by the formation of cold abscesses or fistulas, as well as granulomatous tissue, reactive fibrosis, and necrosis, which can resemble local malignancy. Cutaneous actinomycosis in the trunk or extremities is extremely rare and is usually related to previous surgical procedures or trauma. However, we report one such rare case of cutaneous actinomycosis of the forearm without previous precipitating factors, which was successfully treated with prolonged antibiotherapy.