Cutaneous tuberculosis in Penang: A 12-year retrospective study

ABSTRACT

Background Cutaneous tuberculosis (TB) is a form of extrapulmonary tuberculosis. Diagnosis of cutaneous TB is often difficult because of the diverse clinical presentations. The positive yields from cultures are often low. To describe the demographic, clinical, histopathological and bacteriological aspects of cutaneous TB. Materials and Methods This retrospective review looked at cases of cutaneous tuberculosis treated at the Respiratory and Dermatology unit, Penang Hospital from 1996 to 2007. Data were analysed with SPSS 13.0 version. Results A total of 23 cases of cutaneous tuberculosis were reviewed. The male to female ratio was 2.3 to 1. The mean age was 37.7 ± 20.7 years. There were 10 Malays, 9 Chinese, 2 Indians and 2 Indonesian. The types of cutaneous tuberculosis observed were lupus vulgaris (47.8%), tuberculides (17.5%), tuberculosis verrucosa cutis (13.0%), scrofuloderma (13.0%) and primary inoculation TB (8.7%). 43.5% of patients had systemic involvement. Mantoux tests were positive in 85.0% of cases. Skin biopsies were performed in 91.3% of patients and 71.4% of them showed classical histopathologic findings suggestive of tuberculosis. Mycobacterium tuberculosis was isolated in the culture from 28.6% of patients. Localized diseases were found more often in BCG-vaccinated individuals. Regional lymphadenopathy was noted more often in patients with disseminated disease. No correlation was found between Mantoux reactivity and the extent of disease. Conclusion Lupus vulgaris was the commonest form of cutaneous tuberculosis. Cultures were positive in only a small proportion of patients. Almost half of our patients had systemic involvement. The presence of regional lymphadenopathy often indicates disseminated disease. Patients without BCG vaccination were at higher risk of disease dissemination.