Stevens-Johnson Syndrome and TEN

Which of the following drugs is the MOST common causative agent of Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis in India?

A 28-year-old woman presents with fever, painful oral ulcers, and a widespread blistering rash involving <10% of body surface area. She had started trimethoprim-sulfamethoxazole for a urinary tract infection 2 weeks ago. What is the most common causative drug class implicated in Stevens-Johnson Syndrome?

A 28-year-old woman from Delhi presents to the emergency department with a 5-day history of high-grade fever, severe oral pain, and difficulty swallowing. On examination, she has extensive erosions of the lips, buccal mucosa, and pharynx with blood-stained crusts. She also has a widespread erythematous rash on her trunk and extremities with target lesions and flaccid blisters. She reports taking trimethoprim-sulfamethoxazole for a urinary tract infection 10 days ago. Her temperature is 39.2°C, heart rate 110/min, and blood pressure 98/62 mmHg. Laboratory investigations show WBC 8,500/μL, hemoglobin 11.2 g/dL, and serum creatinine 1.8 mg/dL. What is the most appropriate immediate management for this patient?

A 35-year-old man with severe TEN (45% body surface area involvement) presents with fever, mucosal ulceration, and rapidly progressive skin necrosis 4 days after starting phenytoin for seizure prophylaxis. The offending drug has been discontinued. Despite aggressive supportive care over 48 hours, the rash continues to spread and new lesions are appearing. Which agent should now be added to the management regimen?

A 28-year-old woman presents with fever, blistering of lips, and painful erosions of the oral mucosa for 3 days following initiation of trimethoprim-sulfamethoxazole for a urinary tract infection. Examination reveals target lesions on the palms and soles, and conjunctival involvement. She is suspected to have Stevens-Johnson Syndrome. Which investigation is most appropriate to confirm the diagnosis?