Hypothyroidism, when severe, produces characteristic non-sunken edema due to infiltration of the skin with mucin and mucopolysaccharide. It often occurs on the face and anterior tibia and is caused by various causes of thyroid insufficiency, resulting in a lack of thyroxine or thyroid hormone resistance, subcutaneous deposition by mucopolysaccharides, and waxy edema of the face. It is most often seen in people with autoimmune thyroid disease, excessive thyroidectomy for hyperthyroidism or excessive destruction by radiotherapy. The most common of these are thyroid autoimmune diseases, such as Hashimoto’s thyroiditis, which are often accompanied by an enlarged thyroid gland. As the disease progresses, thyroid cells are gradually destroyed and reduced, and a shrinking fibrous thyroid gland may also appear, eventually leading to hypothyroidism or loss of thyroid function.