DRESS syndrome due to first-line antitubercular therapy - A diagnostic imbroglio!

Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome after the use of first-line antitubercular drugs (ATDs) is rare and literature regarding DRESS syndrome due to ATDs is scarce in children. We report a young boy with tuberculosis who developed DRESS syndrome after exposure to isoniazid. A 9-year-old boy, diagnosed clinically as pulmonary tuberculosis, presented with fever, fast breathing, maculopapular rash, and one episode of gross hematuria. He had been on 4-drug ATD therapy (isoniazid, rifampicin, ethambutol, and pyrazinamide) for the past 4 weeks. In view of multiorgan involvement and absence of a microbiological diagnosis of tuberculosis, vasculitis was considered and he was treated with steroids. As the child recovered, both corticosteroids and ATD therapy were stopped. At 6 months of follow-up, he was presented with pneumonia. Microbiological diagnosis of tuberculosis was made and 4-drug ATD therapy was reinitiated. After 15 days, he again developed a high-grade fever and rash. On evaluation, isoniazid-induced DRESS syndrome was diagnosed. Subsequently, he received a modified regimen of ethambutol, pyrazinamide, levofloxacin, and linezolid. DRESS syndrome did not recur on these ATDs and the child became asymptomatic. Linezolid was stopped after 3 months of therapy and ethambutol, pyrazinamide, and levofloxacin are being continued. Currently, he has completed 15 months of modified ATD therapy. As a high index of suspicion is required for early diagnosis and management that are crucial to reducing morbidity and mortality, DRESS syndrome should be among the differentials in children with unexplained febrile illnesses.