Cutaneous tuberculosis: Epidemiology, pathogenesis, clinical features and investigations.

Cutaneous tuberculosis (CTB) is an important type of extrapulmonary tuberculosis (EPTB), especially in countries where the tuberculosis (TB) load is high. It is reported from all over the globe with varying incidence, affecting all age groups, and it presents with different clinical forms depending upon the host, environmental and pathogen-related factors. Diagnosis of CTB, especially in atypical forms, is a challenge, even with newer molecular methods, as most cases are paucibacillary. CTB can be considered a neglected disease as there is a paucity of epidemiological data, awareness and research about it. With an aim to end tuberculosis in the near future, it is important to understand the distribution and determinants of CTB. This article, the first of two articles on this subject, reviews the present literature on epidemiology, pathogenesis, clinical features and types of CTB, including its associations and investigations.