Apparently normal skin in lepromatous leprosy: histopathological findings

Biopsy specimens of apparently uninvolved skin from 34 patients with lepromatous leprosy were studied histologically. Bacilli were found in 30 of 31 specimens from clinically polar or near-polar lepromatous patients but not in the three from nonpolar patients. A predominantly perivascular distribution of infiltrate and bacilli is consistent with a hematogenous spread of infection. Subclinical, diffuse lepromatous leprosy is found in patients with nodular lesions and may precede the development of nodules. Study of apparently uninvolved skin may be helpful in classifying patients, in interpreting immunologic responses, and in elucidating the natural history of the illness.