Microscopic leprosy skin lesions in primary neuritic leprosy.

The histologic diagnosis of primary neuritic leprosy (PNL) remains a public health care concern, especially when nerve biopsies cannot be performed. As such, some authors emphasize the importance of performing a skin biopsy of a hypoesthetic area even without clinically visible lesions. In this study, an attempt was made to define the histologic changes in the sensory altered skin of 42 clinically diagnosed PNL patients. Histologic alterations caused by leprosy were seen in 31% of these patients: 6 were classified as borderline tuberculoid and 7 as indeterminate. In addition, 33% showed mild, non-specific, mononuclear cell infiltrates around the blood vessels within the papillary and reticular dermis that probably reflected an early inflammatory reaction to Mycobacterium leprae infection. Only 36% of those biopsied had no significant lesions. Our results suggested that, while not all PNL patients are similar, histologic skin examination can contribute to early leprosy detection and commencement of adequate treatment.