Because of the large variability in host immune response to M. leprae, patients present with heterogeneous clinical manifestations of disease. The period between infection and overt disease varies widely from several months to 30–40 years. The disease typically affects the skin, nerves, and eyes, and patients may present with skin lesions, weakness or numbness, eye pain, or loss of vision. The clinical diagnosis of leprosy should always be suspected in someone with skin lesions and/or enlarged nerves accompanied by sensory loss.[17,18,19]
At the paucibacillary tuberculoid end of the spectrum of disease, patients can have one to several large asymmetric skin lesions, typically macules or plaques, with sharply defined borders and hypopigmented, anesthetic centers. In borderline tuberculoid, the most common form of leprosy, skin lesions resemble those of tuberculoid leprosy but are more frequent and variable in appearance with less well-demarcated borders. Asymmetric enlargement of peripheral nerves and progressive nerve damage are common, and patients may present with muscle weakness or trauma secondary to sensory impairment. Progressing toward the multibacillary lepromatous end of the spectrum, patients with the midborderline form are immunologically unstable and may shift rapidly toward the borderline tuberculoid end of the spectrum during a reversal reaction (Figure 1). Skin lesions are numerous; vary in size, shape, and distribution; and may be hypopigmented or erythematous.
A characteristic "target lesion," typically present in patients with the midborderline form of leprosy, has a broad, erythematous border with a vague outer edge and a punched-out pale center with sensory impairment. Patients with the borderline lepromatous form also have numerous skin lesions, generally with intact sensation, although occasionally lesions may exhibit hypoesthesia. Patients at the lepromatous end of the disease spectrum have extensive disease and widespread involvement of the skin and other organs. Generalized infiltration of the dermis may cause the skin to have a smooth, shiny appearance. Numerous skin lesions (macules, papules, or nodules) are symmetrically distributed, but with retained sensation. Progressive thickening of the skin causes coarse facial features and thickening of the ear lobes. Eyebrows and eyelashes are thinned out, and infiltration of the nasal mucosa may occur, resulting in discharge and obstruction. Erosion of the cartilage and nasomaxillary bones can result in perforation of the nasal septum, collapse of the nose, and saddle-nose deformity. Extension into the eye can cause keratitis and iritis. Infiltration of dermal nerves can cause peripheral sensory loss.[17,18]
Pharmacotherapy. 2012;32(1):27-37. © 2012 Pharmacotherapy Publications