The use of anti-tubercular therapy (ATT) as a diagnostic tool in pediatric cutaneous tuberculosis

A 12-year-old boy was seen with a discharging ulcer over the thoracic spine on July 5, 2002. The boy was apparently well 4 days before, when his mother accidentally noticed a small boil on the middle of the spine, surrounded by erythema and edema. The swelling increased until it burst 1 day prior to the examination, emitting a purulent discharge. The patient had fever with profuse sweating. There was no history of cough or expectoration, nausea, and/or vomiting. There was a history of recurrent chest pain, which was a consequence of pulmonary pathology, as the boy had been taking treatment for a recurrent chest infection for the past 4 years. The parents had also observed a loss of appetite and weight. The child was never vaccinated with bacillus Calmette-Guerin (BCG). His grandfather had succumbed to pulmonary tuberculosis. A history of tuberculosis was elicited in a family friend, as well as in the next-door neighbors. Examination of the skin surface on the back revealed the presence of a 1.5 cm x 1.5 cm ulcer. It had a purulent discharge. The ulcer was angry looking and had everted, undermined, irregular borders. It was tender to the touch and surrounded by erythema and edema. The ulcer was located at the dorso-lumbar spine (Fig. 1a,b). Smear(s) were prepared from the purulent discharge and were stained for the demonstration of acid-fast bacilli (AFB) with Ziehl-Neelsen stain; they were negative on three occasions. Culture result of the purulent discharge showed no growth after 48 h of incubation at 37 degrees C aerobically. Also, hematoxylin and eosin-stained sections prepared from the representative margin of the ulcer were studied to illustrate its microscopic pathology. It was characterized by a bizarre collection of epithelioid cells and partial foreign body giant cell formation (Fig. 2a,b). Typical tubercles per se, however, were conspicuous by their absence, as were caseation necrosis and tubercle bacilli. Chest examination revealed bilateral diminished air entry. Tympanic resonance was decreased. In addition, bilateral and asymmetric crackling and crepitations were demonstrated on auscultation. The crepitations were prominent on the right apical and right lower lobe. These were supported by the postero-anterior view roentgenograph of the chest, which revealed prominence of both hila. Patchy heterogeneous infiltration occupying the para-cardiac area and the right apex was conspicuous. Sputum examination and gastric lavage were negative for AFB. Mantoux test with intradermal injection of 0.1 mL SPAN's tuberculin (purified protein derivative (PPD)/5 tuberculin unit (5TU)/0.1 mL) was negative after 72 h. Investigations, including total and differential leukocyte counts, serum biochemistry, and renal and liver function tests, were within the normal range, except for the erythrocyte sedimentation rate, which was 55 mm/1st hour (Westergren). X-Ray of the lumbo-sacral area was negative. Tuberculosis-enzyme-linked immunoabsorbent assays (TB-ELISA) and polymerase chain reaction (PCR) were also inconclusive. A working diagnosis of scrofuloderma was made. Accordingly, antitubercular therapy (ATT), comprising 150 mg of rifampicin, 100 mg of isonicotinic acid hydrazide, and 500 mg of pyrazinamide (Rinizide Forte-DT), was advised for oral administration daily for a continuous 8-month period. A remarkable regression of the skin lesion was recorded after a period of 12 weeks (Fig. 1a,b). Corresponding regression of the lesions of the lungs was also seen clinically, as well as on roentgenograph. Accordingly, the patient was advised to continue the treatment for another 5 months. The patient has successfully completed the schedule of treatment. The skin and lung lesions have completely subsided. Currently, he is under surveillance.