1 An adenoma is a part of the gland that has walled itself off from the rest of the gland, forming noncancerous (benign) lumps that may cause an enlargement of the thyroid. Not all adenomas produce excess T-4, and doctors aren't sure what causes some to begin producing too much hormone.  Thyroiditis.
Scratching Itchy Skin Causes Brain To Release Hormone Serotonin, Intensifies Itchy Sensation. While a good scratch may temporarily relieve you of your itch, it actually stimulates serotonin in the brain that intensifies the itchy feeling.
Skin conditions. Skin conditions that can cause itching include: 1  dry skin. 2  eczema â where the skin is dry, red, flaky and itchy. 3  contact dermatitis â inflammation of the skin that occurs when you come into contact with an irritant or allergen (see below).