infectious diseases
Extrapulmonary Tuberculosis (TB)
Cutaneous tuberculosis
Cutaneous tuberculosis (scrofuloderma) results from direct extension of an underlying TB focus (eg, a regional lymph node, an infected bone or joint) to the overlying skin, forming ulcers and sinus tracts. Lupus vulgaris results from hematogenous or lymphogenous dissemination to the skin from an extracutaneous focus in a sensitized patient. Tuberculosis verrucosa cutis (prosector's wart) occurs after exogenous direct inoculation of the mycobacteria into the skin of a previously sensitized patient who has moderate to high immunity against the bacilli. Rarely, TB develops on abraded skin in patients with cavitary pulmonary TB. 