To protect itself from the damaging effects of the sun, skin makes more brown pigment, called melanin. That extra melanin is what creates a suntan. But sometimes skin doesn't make melanin evenly. As a result, the skin's coloring, called pigmentation, looks patchy. The sun also can cause small blood vessels to stretch, giving skin a blotchy look.

Melanin is the brown pigment in the top layer of skin that gives skin its color. Melanin protects the deeper layers of skin from sun damage. The more melanin in the skin, the darker the skin looks, and the more protection it has against sun damage.

People with brown or Black skin have more natural protection from the sun than do people with white skin. But brown or Black skin still can be damaged by the sun. Pictured below is an example of brown skin with signs of sun damage, including wrinkles and areas of uneven color.

Solar lentigines (len-TIJ-ih-neez) are flat spots that are darker than the skin around them. They are usually tan, brown or dark brown, depending on skin color. Typically, they are darker than freckles. Solar lentigines usually have oval to round shapes with uneven edges. They can be different sizes. They tend to show up on areas most exposed to the sun, such as the head, face, hands, arms and upper body. Also called liver spots, they are common in older adults. But children with white skin who spend a lot of time in the sun also may develop solar lentigines.

With age and with more time outdoors, people tend to develop more solar lentigines. Sometimes solar lentigines appear in large numbers, as seen on the upper back in the photo below. Solar lentigines are similar to freckles. But unlike freckles, solar lentigines don't tend to fade during colder months.

A labial lentigo is a harmless, small, flat, brown spot on the lip. It's also called labial melanotic macule. It can appear after spending time in the sun. In most cases, labial lentigo forms on the lower lip.

The sun's ultraviolet radiation breaks down the connective tissue — collagen and elastin fibers — that lies in the deeper layer of the skin. Without that supportive connective tissue, the skin loses its elastic quality. This condition is called solar elastosis (e-las-TOE-sis). Skin affected by solar elastosis has deep wrinkles that don't disappear when stretched. The skin also may look yellow.

Melasma (muh-LAZ-muh) is a darkening of skin on the face. It's sometimes called the mask of pregnancy. Dark patches usually appear on the forehead and cheeks. Melasma can get worse after time in the sun.

Melasma often affects:

• Black, Asian and Hispanic people.
• People who use birth control pills or hormone therapy.
• People in their second or third trimester of pregnancy.

Melasma might fade after the birth of a baby, during the winter months or when a person stops taking birth control pills. But melasma also can last for years.

Poikiloderma (POI-kih-loe-DUR-muh) appears as areas of uneven coloring on the skin. It's most common on the areas of the neck and upper chest that are often exposed to sunlight. If those areas continue to be exposed to the sun, poikiloderma can get worse over time.

Actinic keratosis (ak-TIN-ik ker-uh-TOE-sis) looks like a rough, scaly patch on the skin. The color may be from tan or red to brown, depending on skin color. Actinic keratosis also is called solar keratosis. It's commonly found on areas of the skin often exposed to sunlight in people who have white skin. Sometimes, actinic keratosis may develop into a type of skin cancer called squamous cell carcinoma. Because there's no way to tell if one of these patches will become cancer, all actinic keratoses need treatment. Make a medical appointment if you notice a patch on your skin that could be actinic keratosis.

Lentigo maligna is a type of growth that develops on areas often exposed to the sun over a long period of time, including the face, arms and legs. Lentigo maligna starts as a flat spot with an uneven shape that slowly gets bigger. When it first appears, a lentigo maligna usually is brown or brown-black. Later, it might develop red and white patches. Over time, the spot may turn into melanoma. Melanoma is a type of skin cancer that begins in the top layer of skin. It then moves to the layers of skin underneath.

See your health care professional if you notice:

• A new skin growth.
• Changes to a mole you already have, such as a change in size, shape or color.
• A mole that bleeds or becomes itchy or painful.
• Any skin changes that are out of the ordinary for you.