Cutaneous Manifestations of Antitubercular Drugs and Their Relationship with Respiratory Compliance: An Observational Study

Background: Cutaneous adverse drug reactions (CADRs) are a clinically significant complication in patients undergoing antitubercular therapy (ATT), with implications for both treatment adherence and respiratory health. This study aimed to characterize the spectrum of CADRs in patients receiving ATT and evaluate their relationship with respiratory system compliance. Methods: A prospective observational study was conducted at a tertiary care center in North India, enrolling 100 patients who developed cutaneous symptoms following ATT initiation. Data collected included demographics, ATT regimens, type and severity of CADRs, suspected culprit drugs, and pulmonary parameters—specifically respiratory system compliance and forced expiratory volume in 1 second (FEV₁). Statistical analyses included ANOVA, logistic regression, and correlation assessments. Results: The cohort included 46 males and 54 females, with a mean age of 41.9 ± 15.4 years. The most frequent CADRs were maculopapular eruptions (35%), urticaria (19%), hyperpigmentation (18%), and exfoliative dermatitis (17%). Severe CADRs occurred in 15% of patients and were associated with a significantly greater decline in respiratory compliance (mean change: 9.0 ± 2.5 ml/cmH₂O, p < 0.001) and lower FEV₁ (% predicted: 59.7 ± 10.8 in severe vs. 74.6 ± 7.6 in mild cases, p < 0.001). Isoniazid and rifampicin were the most frequently implicated drugs. No independent predictors of severe CADRs were statistically significant in multivariate analysis. Overall, 70% of patients recovered fully, 17% had ongoing symptoms, 8% required modification of ATT, and 2% experienced fatal outcomes. Conclusions: CADRs during ATT are common and can have measurable systemic effects, including impaired respiratory function. Early identification and stratification of CADRs—especially severe forms—are critical for guiding individualized therapy and minimizing morbidity. Integrating dermatologic and respiratory monitoring may improve outcomes in TB management.