Itchy and dry skin is another common symptom of hypothyroidism. This has to do with skin turnover, Dr. Hall says. “It slows down which means there are older cells still on the skin.” You may find your nails very breakable all of a sudden. Insufficient thyroid hormone slows down metabolism, which reduces sweating. The dryness can be extreme, this may cause no sweating and the palms and soles to get thick and dry.