Primary granulomatous dermatitis caused by Rhodochrous. Evidence for a pathogenic role in humans.

Bacteria belonging to the Rhodochrous complex are of uncertain taxonomic status. Currently excluded from the genus Mycobacterium, these organisms are more closely allied to Nocardia. Organisms of the Rhodochrous complex have only rarely been implicated as human pathogens. An 81-year-old man had a plaquelike cutaneous granuloma from which Rhodochrous was both cultured and demonstrated in tissue section. A pathogenic role for Rhodochrous causing a primary cutaneous infection is suggested. Specific antimicrobial treatment with doxycycline hydrochloride was successful and there has been no recurrence of the infection after three years.