A 40-year-old gentleman, non-smoker, with history of 10 kg weight loss, underwent chest radiograph. He had no other symptoms. Chest radiograph showed widened right paratracheal stripe. Intradermal tuberculin test performed, using 5 tuberculin units, showed a strongly positive reaction with formation of bulla by 12 hours, and induration of 40 x 30 mm by 24 hours (Figure 1). Magnetic resonance imaging of thorax showed enlarged heterogeneous, necrotic lymph node in the right paratracheal location meausring 30 x 30 mm (Figure 2). The endobronchial ultrasound guided transbronchial needle aspiration from the right paratracheal lymph node revealed pus which showed acid fast bacilli, and he was started on anti-tubercular therapy.DiscussionMantoux test is an example for the delayed hypersensitivity reaction to the tuberculin test.1,2 Most develop mild erythema and induration by 24 hours, which peaks at 48 to 72 hours. Our patient had massive bullous response following mantoux testing.This strong reaction is common in patients with active tuberculosis, having high mycobacterial antigen load as in our patient.3 Although mantoux test is a sensitive but non-specific test, in the diagnosis of active tuberculosis, it needs to be correlated to the patients clinical context for assisting the diagnosis. Figure 1: Mantoux test administered over the left forearm showing bullous reaction Figure 2: Magnetic resonance imaging of thorax showed enlarged heterogeneous, necrotic lymph node in the right paratracheal location

A 40-year-old gentleman, non-smoker, with history of 10 kg weight loss, underwent chest radiograph. He had no other symptoms. Chest radiograph showed widened right paratracheal stripe. Intradermal tuberculin test performed, using 5 tuberculin units, showed a strongly positive reaction with formation of bulla by 12 hours, and induration of 40 x 30 mm by 24 hours (Figure 1). Magnetic resonance imaging of thorax showed enlarged heterogeneous, necrotic lymph node in the right paratracheal location meausring 30 x 30 mm (Figure 2). The endobronchial ultrasound guided transbronchial needle aspiration from the right paratracheal lymph node revealed pus which showed acid fast bacilli, and he was started on anti-tubercular therapy.DiscussionMantoux test is an example for the delayed hypersensitivity reaction to the tuberculin test.1,2 Most develop mild erythema and induration by 24 hours, which peaks at 48 to 72 hours. Our patient had massive bullous response following mantoux testing.This strong reaction is common in patients with active tuberculosis, having high mycobacterial antigen load as in our patient.3 Although mantoux test is a sensitive but non-specific test, in the diagnosis of active tuberculosis, it needs to be correlated to the patients clinical context for assisting the diagnosis. Figure 1: Mantoux test administered over the left forearm showing bullous reaction Figure 2: Magnetic resonance imaging of thorax showed enlarged heterogeneous, necrotic lymph node in the right paratracheal location