Cutaneous Tuberculosis: An Evaluation of 7 Cases

Sir, While mycobacteria l infection has been known to cause cutaneous disease for \150 y, the terminology and classiŽ cation of cutaneous tuberculosis (TB) are still controversial (1–4). Beyt et al. (1) classiŽ ed cutaneous TB in a practical and comprehensive manner in 1981. This classiŽ cation considered clinical appearance, histology and associated Ž ndings and also used the same terms previously used in the literature. However , this classiŽ cation does not include cutaneous TB from paradoxica l expansion (5). Our recently suggested addition to this classiŽ cation has been published in this journal (6). In the present contribution we review 7 patients with cutaneous TB followed in our unit between 1982 and 2001 and classify them using our new classiŽ cation (6), which is principally based on that of Beyt et al. (1). During the last 20 y we have followed 264 patients with TB, 209 of whom (79%) had extrapulmonary TB. Seven (3%) of these 209 patients with extrapulmonary TB had cutaneous disease. The clinical features, diagnosis, treatment and outcomes of these patients are shown in Table I. The distribution of the patients according to the new classiŽ cation is shown in Table II. Case 1 represents cutaneous TB from an exogenou s source. This patient had a non-healing ulcerated cutaneous lesion for 2 y on his right foot, and also developed subcutaneous abscesses between this ulcer and the inguinal region. The abscesses cultured Mycobacterium tuberculosis. Cases 2–4 had TB from an endogenou s source: they all had cervica l masses of 2–3 months duration. Cutaneous lesions and draining sinuses developed within 2–3 weeks. Samples of the draining sinuses were positive for acid-fast bacilli for cases 2 and 4; the histology was necrotizing granulomatous adenitis in cases 2 and 3. Culture was negative and PCR was not done. Case 5 developed cutaneous TB during hematogenou s spread of pulmonary TB. Cases 6 and 7 had cutaneous TB lesions due to paradoxica l expansion . All 7 patients were administered quadruple (isoniazid and rifampicin for 9–12 months; pyrazinamide and ethambutol for the Ž rst 2 months) anti-TB therapy. Case 7 additionally required surgical debridement . Outcomes were assessed clinically; all patients improved within 2–3 months. Clinical suspicion is the mainstay of diagnosis in cutaneous TB. A detailed microbiologica l study (Ziehl–Neelsen staining, TB culture and PCR) of the clinical sample (pus or tissue) is needed (1–5). The histology of the tissue should also be examined (1–3, 7). Detection of caseating granulomas is diagnostic. Ziehl–Neelsen staining and PCR studies of the granulomatous tissue should also be done when available (7). The principles of therapy for cutaneous TB are similar to those for pulmonary TB and include combination chemotherapy (2, 3). The duration of therapy for cutaneous TB resulting from hematogenou s spread should be 1 y. In conclusion , cutaneous TB should be considered when cutaneous ulcers, lesions or abscesses with draining sinuses, with a subacute:chronic course, not responding to antibiotics and surgical drainage and with non-tuberculous cultures are encountered .