Application of Allele-Specifi c Polymerase Chain Reaction for Rapid Differentiation of Mycobacterium Leprae from Mycobacterium Tuberculosis

Leprosy (Hansen’s disease) is a chronic granulomatous infection caused by Mycobacterium leprae affecting primarily skin and nerves. Leprosy is an important clinical problem and is also a challenging diagnostic problem for clinicians. Clinically, leprosy might at times be diffi cult to be distinguished from lupus vulgaris. We report a 70-year-old woman who showed a well-demarcated erythematous enlarging plaque on left peri-ocular region suggesting leprosy resembling lupus vulgaris. Skin biopsy was performed and mycobacterial infection was identifi ed. However, it was uncertain to differentiate between tuberculosis and leprosy. To solve the problem, we design an allele-specifi c polymerase chain reaction based on two-nucleotide difference between bacilli of TB and leprosy. Our result showed allele-specifi c polymerase chain reaction can rapidly differentiate the infection caused by M leprae or by M tuberculosis. (Dermatol Sinica 27: 170-175, 2009)