IgA vasculitis mimicking drug-induced skin reaction and infectious colitis in an elderly patient: A case report.

RATIONALE: Immunoglobulin A vasculitis (IgAV) in adults is rare and shows worse symptoms and prognosis. In real-life clinics, IgAV in elderly patients may be difficult to diagnose because of its rarity and other common diseases to consider. This study reports a case of IgAV mimicking drug-induced skin reaction in an elderly patient. PATIENT CONCERNS: A 74-year-old female without any underlying disease presented to our emergency department as she was suffering from lower abdominal pain and diarrhea for 3 weeks. The patient was diagnosed with infectious colitis, and antibiotic treatment was administered at a local clinic. At presentation, the patient had rashes on both lower legs that developed after the antibiotic treatment, which was assumed as a drug eruption. Although antibiotic treatment was continued, the patient had persistent abdominal pain, diarrhea, hematochezia, and rashes. Proteinuria was developed on urinalysis. DIAGNOSES: Infectious colitis, IgAV. INTERVENTIONS: Sigmoidoscopy revealed easily bleeding erythematous mucosal lesions from the descending colon to the rectum. IgAV was suspected, and thus skin biopsy was performed. Histological findings of the skin biopsy showed leukocytoclastic vasculitis, which is compatible with IgAV. A nonsteroidal anti-inflammatory drug was administered for abdominal pain. The patient showed persistent proteinuria and a systemic steroid (prednisolone 50 mg [1 mg/kg]) was started. OUTCOMES: After administration of the nonsteroidal anti-inflammatory drug, the patient's abdominal pain was resolved rapidly. Under systemic steroid treatment, the patient showed significant symptomatic improvements, and after 2 weeks, the skin and colonic mucosal lesions were completely resolved. LESSONS: We present a case of adult-onset IgAV, which was initially diagnosed with infectious colitis and drug eruption. The history of skin reaction development after antibiotic treatment and the rarity of IgAV in elderly patients masked the diagnosis of IgAV. Despite its rarity, IgAV should be highly suspected in elderly patients with rashes, proteinuria, and signs of colitis.