Background. Acute suppurative thyroiditis in children is rare and is often related to a pyriform sinus fistula or thyroglossal duct remnant, especially when it is recurrent. Methods. From January, 1985, through December, 2000, 15 children with acute suppurative thyroiditis were treated. Their clinical, laboratory and radiologic findings were reviewed and analyzed. Results. There were 8 girls and ... [Show full abstract] 7 boys, with a mean age at diagnosis of 6.1 +/- 2.9 years (range, 1.5 to 9.8). A thyroid mass was present on the left in 13 and on the right in 2 (P < 0.05). Fever, neck pain and swelling were the most common symptoms and signs. Seven patients (46.7%) had recurrent disease. Needle aspiration for Gram stain and bacterial cultures were done, and pathogenic organisms were identified on culture in 8 patients but were found only on Gram stain in 2 patients. In one-half of the patients with positive cultures, mixed pathogens were found. The most common organisms isolated were streptococcal species (50%). Barium esophagography was performed in all patients, and 5 (33.3%) had a pyriform sinus fistula on the left. Only 1 of the recurrent patients had a fistula. Thyroid scans were performed in 13 patients, of whom 12 (92.3%) had decreased radioactive uptake. Thyroid function tests were normal in all 15. Conclusions. Acute suppurative thyroiditis is usually caused by oropharyngeal flora, resulting in mixed pathogens on culture. Broad spectrum antibiotics should be given once cultures have been obtained. Imaging studies might be helpful in the diagnosis of acute suppurative thyroiditis.