Cutaneous tuberculosis: a twenty-year prospective study.

SETTING: A tertiary care hospital in northern India.
OBJECTIVE: To study the patterns of clinical presentation of cutaneous tuberculosis, to correlate them with Mantoux reactivity and BCG vaccination status, and to suggest a clinical classification based on these factors.
DESIGN: Analysis of the records of patients with cutaneous tuberculosis who attended the hospital between 1975 and 1995.
RESULTS: A total of 0.1% of dermatology patients had cutaneous tuberculosis. Lupus vulgaris was the commonest form, seen in 154 (55%) of these patients, followed by scrofuloderma in 75 (26.8%), tuberculosis verrucosa cutis in 17 (6%), tuberculous gumma(s) in 15 (5.4%) and tuberculids in 19 (6.8%). No correlation was found between Mantoux reactivity and the extent of disease (localised disease 63.6%, disseminated disease 67.9%). The presence of regional lymphadenopathy was an indication of dissemination of the disease (localised disease 34.7%, disseminated disease 71.7%). Dissemination of the disease was observed in the whole of the spectrum of cutaneous tuberculosis (22.1%), but was seen more often in the presence of gumma and scrofuloderma. There were more unvaccinated individuals in the group with disseminated disease (80.3%) than in those with localised disease (65.5%).
CONCLUSIONS: Lupus vulgaris was the most common clinical presentation, followed by scrofuloderma, tuberculids, tuberculosis verrucosa cutis and tuberculous gumma. Some patients presented more than one clinical form of the disease. Classification of cutaneous tuberculosis needs to be modified to include smear-positive and smear-negative scrofuloderma apart from the inclusion of disseminated disease. The presence of regional lymphadenopathy serves as a clinical indicator of disseminated disease. Patients with disseminated disease were less likely to have been BCG-vaccinated than those with localised disease.