Cutaneous Adverse Drug Reactions in Patients with Pulmonary Tuberculosis Receiving First-Line Anti-Tubercular Therapy: A Prospective Observational Study

Background: Tuberculosis (TB) continues to rank among the foremost infectious causes of death across the globe, and India is responsible for roughly one quarter of the worldwide burden. Standard first-line anti-tubercular therapy (ATT) is highly effective, yet its benefit is often undermined by adverse drug reactions (ADRs). Reactions involving the skin are among the most frequent of these, ranging from simple itching to life-threatening severe cutaneous adverse reactions (SCARs). When such reactions are overlooked or poorly managed, treatment may be interrupted, adherence may weaken and clinical outcomes may deteriorate. This study was undertaken to establish the incidence, clinical patterns, timing of onset and suspected causative drugs of cutaneous ADRs among pulmonary TB patients on first-line ATT, and to explore whether sex was associated with their occurrence. Material and Methods: This prospective observational study was carried out at a tertiary care hospital and enrolled 150 newly diagnosed, treatment-naïve pulmonary TB patients aged 18 to 65 years. Every participant was given the standard daily fixed-dose combination ATT prescribed under the National TB Elimination Programme (NTEP) and was reviewed each month for six months. For every Cutaneous ADR, the morphology, severity, time of onset and suspected drug were recorded, and the likelihood of a causal link was graded with the Naranjo scale. Associations between categorical variables were examined with the chi-square test or Fisher’s exact test. Results: Cutaneous ADRs developed in 33 of the 150 patients (22.00%). Maculopapular rash was the most frequent pattern (42.42%), followed by urticaria (27.27%) and pruritus without rash (15.15%); four patients experienced a severe cutaneous reaction. The great majority of reactions (87.88%) began within the first month of treatment. Cutaneous ADRs affected 29.31% of females and 17.39% of males, a difference that did not reach statistical significance (p = 0.086). Isoniazid was the drug most often suspected (36.36%), followed by rifampicin (27.27%). Conclusion: Roughly one in five patients on first-line ATT developed a Cutaneous reaction, most often a maculopapular rash, and nearly nine in ten of these appeared during the first month. Isoniazid and rifampicin were the principal suspected agents, and the higher rate among women (29.31% versus 17.39%) was not statistically significant. Structured dermatological surveillance, concentrated in the first month of therapy, is needed so that reactions can be detected and treated promptly and adherence can be safeguarded.

Keywords: Tuberculosis, Cutaneous adverse drug reactions, Anti-tubercular therapy, Pharmacovigilance.