Title : Diagnostic dilemma in cutaneous tuberculosis
The incidence (new and relapse) rate of tuberculosis in Sri Lanka in 2016 was 40.9 per 100,000 population (8332 new and 328 relapse cases). Out of 8332 diagnosed patients with TB, 2525 (30.3%) were in extrapulmonary sites. The annual risk of TB incidence at the national level remains 1.8 percent. Still continue to be a major health issue in Sri Lanka.
Cutaneous TB is classified according to their clinical presentation (cutaneous or subcutaneous) which depends on host immune response. Lupus vulgaris and warty TB (TVC) are the most common clinical manifestations in our setting while other manifestations of cutaneous TB such as scrofuloderma, tuberculous gumma, orificial TB, acute miliary TB, and tuberculids were seldom seen in Sri Lanka. Cutaneous TB can mimic other granulomatous diseases clinically and histopathologically.
I present here images and workup of 30 patients who were histopathologically and therapeutically confirmed to have cutaneous TB. Although positive results of ESR, Mantoux reactivity, and TB cultures facilitate the clinical diagnosis, negative results should not exclude the diagnosis of cutaneous TB. More than 50% clinical improvement noted within 4 weeks of anti TB therapy while total disappearance noted within 8 weeks of anti-TB therapy in 80% of cases.
Therefore alternative cause should be considered if the clinical response to anti-TB drugs is inapparent within 4 weeks. In the situation of limited investigative facilities, clinicohistopathological correlation with therapeutic response is the key to confirming cutaneous TB.