1. Skin Cancers

2. Actinic Keratosis Chronic sun exposure is the cause of almost all actinic keratoses. Sun damage to the skin is cumulative, so even a brief period in the sun adds to the lifetime total. The ultraviolet radiation given off by the lamps in a tanning salon can be even more dangerous than the sun, so dermatologists warn against indoor tanning.

3. Basal Cell Carcinoma The most common form of skin cancer abnormal, uncontrolled growths or lesions that arise in the skin’s basal cells, which line the deepest layer of the epidermis (the outermost layer of the skin). BCCs often look like open sores, red patches, pink growths, shiny bumps, or scars.

4. 5 warning signs of BCC An open sore that bleeds, oozes, or crusts and remains open for a few weeks, only to heal up and then bleed again. A persistent, non­–healing sore is a very common sign of an early BCC. A reddish patch or irritated area, frequently occurring on the face, chest, shoulders, arms, or legs. Sometimes the patch crusts, and it may also itch. At other times, it persists with no noticeable discomfort.

5. A shiny bump or nodule that is pearly or translucent and is often pink, red, or white. The bump can also be tan, black, or brown, especially in dark-haired people, and can be confused with a mole. A pink growth with a slightly elevated rolled border and a crusted indentation in the center. As the growth slowly enlarges, tiny blood vessels may develop on the surface.

6. A scar-like area that is white, yellow or waxy, and often has poorly defined borders; the skin itself appears shiny and taut. This warning sign may indicate the presence of an invasive BCC that is larger than it appears to be on the surface.

7. Melanoma The most dangerous form of skin cancer, these cancerous growths develop when unrepaired DNA damage to skin cells (most often caused by ultraviolet radiation from sunshine or tanning beds) triggers mutations (genetic defects) that lead the skin cells to multiply rapidly and form malignant tumors. These tumors originate in the pigment-producing melanocytes in the basal layer of the epidermis. Melanomas often resemble moles; some develop from moles.

8. The majority of melanomas are black or brown, but they can also be skin-colored, pink, red, purple, blue or white. Melanoma is caused mainly by intense, occasional UV exposure (frequently leading to sunburn), especially in those who are genetically predisposed to the disease. Melanoma kills an estimated 8,790 people in the US annually.

9. If melanoma is recognized and treated early, it is almost always curable, but if it is not, the cancer can advance and spread to other parts of the body, where it becomes hard to treat and can be fatal. While it is not the most common of the skin cancers, it causes the most deaths.

10. If you draw a line through this mole, the two halves will not match. The borders of an early melanoma tend to be uneven. The edges may be scalloped or notched.

11. Having a variety of colors is another warning signal. A melanoma may also become red, blue or some other color Melanomas usually are larger in diameter than the size of the eraser on your pencil (1/4 inch or 6 mm), but they may sometimes be smaller when first detected.

12. Any change — in size, shape, color, elevation, or another trait, or any new symptom such as bleeding, itching or crusting — points to danger.