Cutaneous Mycobacterium haemophilum infection involving the upper extremities: diagnosis and management guidelines.

Mycobacterium haemophilum is a nontuberculous organism that commonly manifests as cutaneous lesions and subcutaneous nodules in immunosuppressed adults. Because M haemophilum infection is rare, the epidemiology, reservoir, and mode of transmission remain largely unknown. Infection presents a challenge to the dermatology community because it is infrequently suspected and commonly misidentified, resulting in delayed diagnosis. We discuss 3 cases of cutaneous M haemophilum infection to better understand clinical presentation, diagnosis, and management.