de Quervain thyroiditis, also known as subacute thyroiditis, is a self-limited 
inflammatory disease of the thyroid gland. It is extremely rare in children. The 
hallmarks for diagnosis are painful thyroid enlargement, elevated inflammatory 
markers, and decreased uptake of the thyroid gland on thyroid scintigraphy. 
Viral infection has been proposed to be associated with de Quervain thyroiditis. 
Coxsackie virus has been reported to be one of the viruses associated with the 
disease. To our knowledge, childhood de Quervain thyroiditis associated with 
hand-foot-mouth disease caused by coxsackie infection has never been reported. 
We report a 2.7-year-old boy who presented with typical features of de Quervain 
thyroiditis following hand-foot-mouth disease caused by coxsackie B4 infection. 
He had a brief thyrotoxic phase initially, followed by transient hypothyroid 
phase and euthyroidism thereafter. His thyroid scintigraphy showed a typical 
faint uptake at the diagnosis, and an improvement of the thyroid scan and uptake 
was shown 8 weeks later. He was treated with prednisolone and nearly complete 
resolution was documented within 2 months. Careful evaluation of the patient led 
to the correct diagnosis and appropriate management.