Find possible causes of numbness or tingling in hands based on specific factors. Check one or more factors on this page that apply to your symptom. Numbness or tingling. 1  Affects both hands. 2  Affects one hand.  Is intermittent.
These cells produce melanin, the substance that gives skin its color. Skin with too much melanin is called hyperpigmented skin. Skin with too little melanin is called hypopigmented skin. Pale skin areas are due to too little melanin or underactive melanocytes. Darker areas of skin (or an area that tans more easily) occurs when you have more melanin or overactive melanocytes. Bronzing of the skin may sometimes be mistaken for a suntan.
Sometimes the hair in these areas also turns white. It happens when the skin's pigment-producing cells called melanocytes die. White patches can appear anywhere on the body (generalized vitiligo) or just in one area (focal vitiligo). Researchers suspect that vitiligo is one of many autoimmune diseases.he exact cause of vitiligo is unknown at this time; however, scientists have several different theories. One theory suggests that vitiligo is an autoimmune disease in which the body destroys melanocytes for no known reason.