Hansen's disease (Leprosy): current and future pharmacotherapy and treatment of disease-related immunologic reactions.

Hansen's disease, also known as leprosy, remains an important public health problem throughout the world, including North America. The causative microbe in Hansen's disease is Mycobacterium leprae, an acid-fast organism that is difficult to grow in vitro. The nine-banded armadillo is the major animal reservoir in the United States. Manifestations of disease vary based on host immune response and can range from tuberculoid to lepromatous leprosy (paucibacillary to multibacillary disease). Hansen's disease typically affects the skin, nerves, and eyes, and patients may present with skin lesions, weakness, numbness, eye pain, or loss of vision. Definitive diagnosis is based on a combination of physical examination findings and skin biopsy and/or smear. Modern antibacterial therapy typically consists of combinations of dapsone and rifampin with or without clofazimine. Clofazimine is available only as an investigational drug through the National Hansen's Disease Program. Other options include moxifloxacin, ofloxacin, minocycline, and clarithromycin. Hansen's disease is associated with type 1 (reversal) and type 2 (erythema nodosum leprosum) immunologic reactions, during which the disease process appears to worsen dramatically. These reactions may occur at any time before, during, or after treatment. Antibacterial therapy should usually be continued during these reactions. Treatment options for these reactions differ based on clinical manifestations and include corticosteroids, thalidomide, pentoxiphylline, tumor necrosis factor inhibitors, and T cell inhibitors. Prompt diagnosis, antimicrobial therapy, and treatment of reactions dramatically reduce complications of the disease.