In TT leprosy, the advancing edge of a skin lesion should be biopsied. In LL leprosy, biopsy of even normal-appearing skin often yields positive results. Serology, skin testing, and PCR of the skin offer little diagnostic assistance.
Treatment: Leprosy Drugs - Rifampin (600 mg daily or monthly) is the only agent bactericidal against M. leprae. See the preceding section on M. tuberculosis for more details on rifampin.
- Monotherapy with dapsone (50-100 mg/d) results in a resistance-related relapse rate of only 2.5%.
- - A decrease in hemoglobin levels of ~1 g/dL is a common adverse effect; the sulfone syndrome (high fever, anemia, exfoliative dermatitis, and a mononucleosis-type blood picture) occurs rarely.
- - G6PD deficiency must be ruled out before therapy to avoid hemolytic anemia.
- Clofazimine (50-100 mg/d, 100 mg 3 times per week, or 300 mg monthly) is a phenazine iminoquinone dye that is weakly active against M. leprae. Adverse effects include red-black skin discoloration.
Regimens Given the unreliability of skin smears and the lack of accessibility to histopathology in many countries in which leprosy is endemic, treatment regimens are based on the number of lesions present. - Paucibacillary disease in adults (<6 skin lesions) is treated with dapsone (100 mg/d) and rifampin (600 mg monthly, supervised) for 6 months or with dapsone (100 mg/d) for 5 years. For a single lesion, a single dose of rifampin (600 mg), ofloxacin (400 mg), and minocycline (100 mg) is recommended.
- Multibacillary disease in adults (≥6 skin lesions) is treated with dapsone (100 mg/d) plus clofazimine (50 mg/d)—unsupervised—in addition to rifampin (600 mg monthly) plus clofazimine (300 mg monthly)—supervised—for 1 year.
- - Some experts prefer rifampin (600 mg/d) for 3 years and dapsone (100 mg/d) for life.
- - Relapse can occur years later; prolonged follow-up is needed.
- Reactional states
- - Lesions at risk for ulceration or in cosmetically important areas can be treated with glucocorticoids (40-60 mg/d for at least 3 months).
- - If erythema nodosum leprosum is present and persists despite two short courses of steroids (40-60 mg/d for 1-2 weeks), thalidomide (100-300 mg nightly) should be given. Because of thalidomide's teratogenicity, its use is strictly regulated.
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