Leprosy

Test

In developing countries, skin smear services are not always available, and their reliability is often doubtful. Therefore, more and more programmes base their classification on clinical criteria. The essential feature is based on the number of skin lesions.

Test

Wherever possible, histopathology can be a valuable aid to differential diagnosis and for accurate classification of the disease.

Different forms of leprosy are accompanied by specific histopathological pictures: towards the tuberculoid (TT) end of the spectrum, histopathology shows epithelioid cells, well-defined granulomas, Langhans giant cells, and lymphocytes with negative Wade-Fite staining; while towards the lepromatous (LL) end of the spectrum, there are more foamy macrophages and Wade-Fite staining shows mycobacteria.

Nerve biopsy may be done in cases of pure neural leprosy.

Test

Detects Mycobacterium leprae DNA in tissue. Useful to diagnose lepromatous leprosy (LL) but less sensitive to diagnose tuberculoid (TT) or borderline tuberculoid (BT), where the diagnosis is more difficult. Not available in all settings.