Mycobacterium haemophilum infection with cutaneous involvement: two case reports and an updated literature review: Mycobacterium haemophilum skin infection.

Mycobacterium haemophilum (MH) is a slow-growing, non-tuberculous Mycobacterium that most commonly causes infections in immunocompromised patients. The skin is the most prevalent site of infection and can be an isolated presentation or part of a disseminated disease. Herein, we reported a case of isolated MH infection of the hand and a case of disseminated MH infection with multiple skin lesions. In addition, other MH cases with cutaneous involvement over the last 10 years, from 2011-2022, were reviewed and analyzed. Among the 79 included cases, the common skin findings in MH infections included nodules, ulcers, abscesses, swelling, and pustules. Middle-aged patients with iatrogenic immunosuppression from glucocorticoids, mycophenolate mofetil, cyclosporine, and cyclophosphamide are the most susceptible to MH infection, with a higher risk of dissemination to internal organs. Disseminated MH infections commonly present as tenosynovitis, arthritis/arthralgia, or osteomyelitis. There is a lack of strong evidence for treatment; however, triple therapy of quinolone, macrolides, and rifampicin is most often used in clinical practice. The overall prognosis is good. The presence of iatrogenic immunocompromised diseases, lesions involving the proximal limbs, and dissemination of MH infections are associated with worse clinical outcomes.