Cutaneous Tuberculosis

Excerpt

Tuberculosis is an infection caused by Mycobacteria, most commonly Mycobacterium tuberculosis. This infection most commonly involves the lungs. When it involves the skin, it is called cutaneous tuberculosis. It is a rare disease.

The history of cutaneous tuberculosis dates back to 1826 when it was first reported by Laennec. He reported a lesion on his hand that was caused by entry of the causative organism into his skin. However, the causative organism was not known until 1882 when Robert Koch first discovered M. tuberculosis. Later, it was isolated from a cutaneous lesion of an affected person.

Classification

Although there are various classification systems, the most universally used classification of cutaneous tuberculosis variants is based on the following:

1. Exogenous cutaneous tuberculosis: Tuberculous chancre and tuberculosis verrucosa cutis

2. Endogenous cutaneous tuberculosis: Contiguity or autoinoculation (scrofuloderma, orificial tuberculosis and some cases of lupus vulgaris); hematogenic dissemination (lupus vulgaris, tuberculous gumma, and acute miliary tuberculosis)

3. Tuberculids: Papulonecrotic tuberculid; Lichen scrofulosorum

4. Cutaneous tuberculosis: Secondary to Bacillus Calmette–Guerin vaccine (BCG) vaccination