Adult-Onset Still's Disease With Normal Ferritin Levels and Severe Sulfasalazine-Induced Probable Case of Drug Reaction With Eosinophilia and Systemic Symptoms (DRESS) Syndrome: A Unique Presentation and Management Challenges.

Adult-onset Still's disease (AOSD) is an uncommon clinical condition with an uncertain cause, characterized by arthritis, fever, evanescent rash, and other systemic presentations. This case report describes a 26-year-old female who had a fever, arthralgia, vomiting, sore throat, bilateral distal extremities edema, hypertension, and normal ferritin. She was diagnosed with AOSD using the Yamaguchi criteria based on exclusion and was treated with hydroxychloroquine and sulfasalazine. The patient's arthralgia improved significantly. However, she returned with complaints of a diffuse erythematous burning, pruritic, maculopapular, non-evanescent rash caused by a severe reaction to sulfasalazine, with a skin biopsy revealing urticarial vasculitis, with probable DRESS (drug reaction with eosinophilia and systemic symptoms) syndrome. This was treated with topical and short-course oral steroids, intravenous antibiotics, and Janus kinase (JAK) inhibitor, improving her condition remarkably. To the best of our knowledge, there are no prior reports of a case of AOSD with normal ferritin levels that also exhibited a severe reaction to sulfasalazine, compounded by complications due to NSAIDs (nonsteroidal anti-inflammatory drugs) and steroid use. This rarity distinguishes our case report.