Skin cancer is the uncontrolled growth of abnormal skin cells. It occurs when unrepaired DNA damage to cells (most often caused by ultraviolet radiation from sunshine or tanning beds) causes mutations, or genetic defects, that prompt the skin cells to multiply swiftly and form malignant tumors. "Once you reach adulthood, you should have a baseline skin check," said Dr. Angela Lamb, director of the Westside Mount Sinai Dermatology Faculty Practice. From there, she would recommend either an annual or every-other-year exam, depending on how you check out and your history.

Whether you abide by this recommendation or not, self-inspection for the signs and symptoms of skin cancer can easily become part of your routine.

Common Symptoms

A change on the skin is the most common sign of skin cancer. This may be a new growth, a sore that doesn't heal, or a change in an old growth. Usually, skin cancer is not painful.

Squamous cell skin cancer begins in squamous cells. In people with dark skin, squamous cell skin cancer is the most common type of skin cancer, and it's usually found in regions of the body that are not exposed to the sun, such as the legs or feet. However, in people with fair skin, squamous cell skin cancer usually occurs on parts of the skin that have been in the sun, such as the head, face, ears, and neck.

Basal cell skin cancer begins in the basal cell layer of the skin. It usually occurs in places that have been in the sun. As such, the face is the most common place to find basal cell skin cancer. In people with fair skin, basal cell skin cancer is the most common type of skin cancer.

Melanomas often resemble moles, and some even develop from moles. The majority of melanomas are black or brown, but they can also be skin-colored, pink, red, purple, blue, or white. Often the first sign of melanoma is a change in the shape, color, size, or feel of an existing mole. A guide to changes in moles can be found here.