Graves' Disease-Associated Acute Necrotizing Ulcerative Gingivitis A Case Report

Acute necrotizing ulcerative gingivitis (ANUG) is predominantly observed in immunocompromised individuals, with antithyroid drug-induced cases being exceptionally rare. Here, we report a unique case of ANUG secondary to methimazole-induced agranulocytosis in an adolescent female with Graves' disease. A 16-year-old female with a 2-year history of Graves' disease, previously treated with radioactive iodine (¹³¹I) and chronic methimazole (10 mg twice daily), presented with fever, pharyngalgia, and severe gingival pain. Laboratory findings revealed agranulocytosis (absolute neutrophil count: 0.15×10⁹/L). Clinical examination demonstrated diffuse grayish-yellow necrotic gingival lesions with deep bone exposure and purulent discharge. Histopathology confirmed necrotic tissue infiltrated by neutrophils and lymphocytes, while blood cultures grew Pseudomonas aeruginosa. Treatment included granulocyte colony-stimulating factor for neutrophil recovery, systemic antibiotics (metronidazole + amoxicillin), and topical hydrogen peroxide/chlorhexidine rinses. Adjunctive therapies included Recombinant human epidermal growth factor gel for mucosal repair, vitamin supplementation, and intensive oral hygiene protocols. Complete resolution was achieved within 4 weeks, with residual bony defects but no functional impairment. Methimazole may induce agranulocytosis through DNA synthesis inhibition or immune-mediated neutrophil destruction, predisposing to ANUG. The polymicrobial etiology necessitates broad-spectrum antimicrobial coverage targeting anaerobes. Multidisciplinary management endocrinology for thyroid control, hematology for neutrophil monitoring, and dentistry for localized debridement is critical for favorable outcomes ANUG may develop without classic risk factors; routine blood monitoring during methimazole therapy is crucial. Multidisciplinary intervention prevents irreversible damage. Rare oral complications require differential diagnosis and endocrine-hematologic evaluation.