Also known as solar keratosis, actinic keratosis affects more than 10 million Americans. These precancerous growths on the skin are caused by overexposure to the sun over a long period of time. They are characterized by rough dry lesions or patches that appear on sun-exposed areas of the skin, such as

Birthmarks are abnormal skin colorations in spots that are either present at birth or appear shortly thereafter. They can be flat or slightly raised from the skin. They can be any number of colors, including red, brown, black, tan, pink, white or purple. Birthmarks are generally harmless. There are two

Also known as skin abscesses, boils form as a result of a cut or break in the skin, which leads to a bacterial infection. They are characterized as a red, tender area with a painful, pus-filled center that can open spontaneously or by surgical incision. Some boils are caused by an ingrown hair. Others

Acne is the most frequent skin condition in the United States. It is characterized by pimples that appear on the face, back and chest. Every year, about 80% of adolescents have some form of acne and about 5% of adults experience acne. Acne is made up of two types of blemishes: Whiteheads/Blackheads,

A blister is a soft area of skin filled with a clear fluid. Blisters may form in response to an irritant. Frequently, the blister is caused from friction, such as a coarse fabric rubbing repeatedly against a person's skin. In other cases, blisters form in response to a chemical or allergic irritant,