Unusual skin infection Unusual mycobacterial infection Unusual mycobacterial skin infection An increased susceptibility to mycobacterial infection of the skin, as manifested by persistent, disseminated, or multifocal cutaneous lesions occurring in an unusual clinical context. This includes skin involvement in tuberculosis (Mycobacterium tuberculosis) or infections caused by atypical mycobacteria (nontuberculous mycobacteria), such as M. marinum, M. avium complex, or M. chelonae. Unusual mycobacterial skin infection Unusual mycobacterial skin infections are highly characteristic of Mendelian susceptibility to mycobacterial disease (MSMD), affecting the IL-12/IFN-gamma axis, as well as GATA2 deficiency and other profound T-cell deficiencies.