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.
1 Allergic reactions may be accompanied by hives or rash. 2  Skin Conditions-Skin conditions such as eczema or sunburn can cause the body to become itchy all over as the body reacts to the condition. 3  Stress or anxiety may stimulate such conditions, leading to itching that is not localized to a particular area.