Children with thick necks are not necessarily hyperthyroidism, but may also be caused by thyroid tumors, obesity, etc., so you need to go to the hospital in time to improve the examination for diagnosis. 1. Hyperthyroidism: it is a group of symptoms caused by excessive secretion of thyroid hormone in childhood, which can lead to hyperappetite, irregular bowel movement, palpitation, fatigue and other uncomfortable symptoms, and some of the patients can also have a big neck, thickening of fingernails, and eyeballs protruding and other special symptoms. 2. Thyroid adenoma: it refers to the tumor growing in the thyroid gland, which is commonly seen in benign thyroid adenoma in clinic, and there is no obvious symptom in the early stage, but with the growth of thyroid adenoma, the volume increases and it can compress the trachea and blood vessels of the children, thus causing a series of uncomfortable symptoms. 3. Obesity: children are in the stage of rapid development, if they do not pay attention to their daily diet, resulting in excessive fat intake, which can cause excessive obesity and excessive fat in the neck area, leading to neck coarsening. So children appear thick neck is not necessarily hyperthyroidism, it is best to take the child to the hospital in a timely manner, after a clear diagnosis for targeted treatment.