Abstract
BACKGROUND: Differential diagnosis of inflammatory bowel disease is often very challenging. Paracoccidioidomycosis is a fungal disease that can mimic manifestations of Crohn's disease. CASE PRESENTATION: We report a case of a 13-year-old Caucasian boy with abdominal pain for 1.5 years associated with nausea, diarrhea, and weight loss of 10 kg. He presented increased C-reactive protein and an increased erythrocyte sedimentation rate. A colonoscopy showed deep serpiginous ulcers throughout his entire colon and rectum, which suggested Crohn's disease. He received one dose of infliximab, which is an anti-tumor necrosis factor-α, and showed no improvement. After the second dose, he got worse and started to have bloody diarrhea. A new colonoscopy was performed and pathological examination revealed ulcerative chronic inflammation with non-caseating granulomas and fungal structures (budding forms) compatible with Paracoccidioides brasiliensis. He underwent intravenously administered and then orally administered trimethoprim-sulfamethoxazole treatment. Due to drug intolerance, he was treated with amphotericin B and itraconazole, then he showed clinical improvement and mucosal healing with good outcome. CONCLUSION: Paracoccidioidomycosis must be part of the differential diagnosis of inflammatory bowel diseases in endemic areas and must be excluded before starting immunosuppressive therapy.