Necrotizing gingivostomatitis and osteonecrosis associated with antithyroid drug propylthiouracil therapy

A 43-year-old Chinese female had been diagnosed with hyperthyroidism 15 years ago. She was recently administered 150 mg/day propylthiouracil (PTU). After 3 weeks of PTU administration, she developed necrotizing stomatitis and osteonecrosis, most likely due to secondary effects from the PTU treatment. Her neutrophil count was reduced below normal to 0.24×10(9)/L but normalized after withdrawal of PTU therapy. About 1 month after onset, the patient came to our hospital and began to receive intravenous treatments of metronidazole and amoxicillin. Following review of her medical history and a series of clinical and laboratory examinations, the patient was diagnosed with secondary necrotizing gingivostomatitis and osteonecrosis possibly associated with PTU-induced agranulocytosis. One-year after treatment, the patient's oral manifestations remained unchanged. This case demonstrates the need for dental practitioners to more closely monitor oral symptoms in patients with hyperthyroidism treated with antithyroid drugs.