A Surprising Case of Mycobacterium Avium Complex Skin Infection in an Immunocompetent Patient
December 2014 | Volume 13 | Issue 12 | Case Reports | 1491 | Copyright © December 2014
Angelo Landriscina BA,a Tagai Musaev BA,a Bijal Amin MD,b and Adam J. Friedman MDa,c
aDepartment of Medicine (Division of Dermatology), Albert Einstein College of Medicine, Bronx, NY
bDepartment of Pathology, Montefiore Medical Center, Bronx, NY
cDepartment of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, NY
Abstract
An acute inflammatory nodule of unknown etiology can pose a formidable diagnostic challenge. Here, we highlight the importance
of including
Mycobacterium avium intracellulare complex (MAC) and other atypical mycobacterial infections in the differential diagnosis
of a cutaneous nodule in an immunocompetent individual. We also explore the implications of eczema in the development
of a mycobacterial infectious process. We report a case of MAC skin infection in an immunocompetent individual. The patient is a
49-year-old male with a history of dyshidrotic eczema presenting with a fluctuant, non-draining nodule on his right forearm for 2 to
3 weeks, identified by tissue DNA probe to be a cutaneous MAC infection without systemic complications, as serologies and chest
X-ray were unremarkable. MAC should be included in the broader differential diagnosis of deep fungal vs atypical mycobacterial skin
infections. Nucleic acid-based assays are an important tool in making a definitive diagnosis, allowing for utilization of appropriate
therapy for the specific etiologic pathogen. Given the patient’s preceding diagnosis of eczema, it is possible that the compromised
skin barrier and dampened cytotoxic Th1 activity predisposed the patient to this infection, typically appreciated in the immunosuppressed,
warranting further investigation into the relative risk for atypical mycobacterial infections in the setting of eczema.
J Drugs Dermatol. 2014;13(12):1491-1493.
INTRODUCTION
Mycobacterium avium intracellulare complex
(MAC) includes 2 genetically similar organisms:
Mycobacterium avium and Mycobacterium intracellulare.
MAC species are widely found in the environment,
and are a major cause of nontuberculous mycobacterial infections
worldwide.1 Although MAC is ubiquitous, it mainly
causes disease in immunocompromised individuals. While
rare, there are reports of varied cutaneous phenotypes including
pustules, plaques or nodules.2,3 Here we present a
notable case of a MAC skin infection in an immunocompetent
patient without disseminated disease.
CASE REPORT
DISCUSSION
