Normal skin contains cells called melanocytes. 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. This skin discoloration often develops slowly, starting at the elbows, knuckles, and knees and spreading from there. Bronzing may also be seen on the soles of the feet and the palms of the hands. The bronze color can range from light to dark (in fair-skinned people) with the degree of darkness due to the underlying cause.