Exposure to types of radiation is associated with developing skin cancer. The sun can cause sunburn.
Melanin is the dark pigment in the outer layer of skin (epidermis) that gives your skin its normal color. When you're exposed to sunlight, your body protects itself by accelerating the production of melanin. The extra melanin creates the darker color of a tan.
A suntan is your body's way of blocking the sun rays to prevent sunburn and other skin damage. But the protection only goes so far. The amount of melanin you produce is determined genetically. Many people simply don't produce enough melanin to protect the skin well. Eventually, sunlight causes the skin to burn, bringing pain, redness and swelling.
You can get sunburn on cool, hazy or cloudy days. As much as 80 percent of sun rays pass through clouds. Snow, sand, water and other surfaces can reflect sun rays, burning your skin as severely as direct sunlight.
Medications that make your skin especially sensitive to the sun's radiation are known as photosensitizers. When you take them, sun exposure can cause overly reddened "sunburned" skin, hives, swelling, and itchy, scaly skin.
Not everyone will have the same degree of sun sensitivity from these medications. But for some, even short intervals of sun exposure can cause a rash or burn. Those who are more at risk include people with fair skin, light-colored hair, and blue eyes; people who work outside; people who live at higher elevations or near the equator; and people with certain autoimmune diseases, such as lupus.
