UV-B is the most damaging and is a common cause of sunburn, suntan, premature aging, skin cancer and eye damage. UV-A, although less harmful, is still dangerous, and contributes to the premature aging of the skin and eye damage. A tan is often mistaken as a sign of good health, but is actually the result of skin injury. Tanning occurs when UV rays enter the skin and it protects itself by producing more pigment or melanin. Freckles, common in people with fair skin, are also signs of sun damage.
Some people also develop allergies to the sun.
An allergic reaction to the sun can occur after a short period of sun exposure and cause bumps, hives, blisters or red blotchy areas on sun-exposed areas. Ultraviolet light rays also cause invisible damage to skin cells, the eyes, and the immune system. Some of the injury is repaired, but irreparable cell damage adds up year after year. Even teenagers and young adults can develop the most dangerous kind of skin cancer called melanoma. As they age, people also develop wrinkles, age spots and cataracts as a direct result of sun exposure.