Vitamin D Toxicity & Rashes

Vitamin D is a fat-soluble vitamin that is produced in your body when sunshine hits your skin. It's then stored in your liver and promotes the absorption of calcium. Vitamin D toxicity occurs when you get too much of the essential nutrient through supplementation. While skin rashes are not a direct result of getting too much vitamin D, sun exposure -- a main way to get the vitamin naturally -- can lead to skin rashes.

Rashes

An ordinary skin rash is typically not serious, but it can feel painful, itchy, and burn. Rashes can be caused by heat and too much sun exposure. A sun rash can occur from direct exposure to UV rays and usually occurs about 10 minutes after you're in the sun. Symptoms include itchy, red skin. People who are prone to skin rashes should avoid sunshine and use at least an SPF 15 whenever they go outside. If you can't get your vitamin D from UV light, you should take a supplement. Before you start a new vitamin regimen, however, you should talk to your doctor.

Toxicity

Michael Holick, M.D., from Boston University Medical Center's Bone Health Care Clinic, says that vitamin D intoxication is one of the most rare conditions in the world. The only way to get toxic amounts of the nutrient is through supplementation. And since so many Americans are deficient in vitamin D, many turn to taking over-the-counter supplements to restore blood levels. Holick reports that 1,000 to 2,000 IU daily is OK for people who are deficient. This amount should not cause toxicity, but since the RDA for adults is slightly lower than that, your chances of hypervitaminosis D are increased -- even more so if you take large doses more than six months at a time. Too much vitamin D could eventually result in renal failure, according to the Merck Manual. Symptoms include a skin rash on the thighs, buttocks and sometimes, knees and elbows.

Sun

You can absorb about 15,000 to 20,000 IU of vitamin D by going out in the sun with exposed arms, legs and torso for 15 minutes, according Holick. Even though this is the easiest method of getting the recommended daily allowance of vitamin D naturally, the Skin Cancer Foundation does not endorse going outdoors for even five to 10 minutes without protection. Since sunscreen ends up blocking about 99 percent of the sun's UV rays, which are responsible for vitamin D synthesis, your alternative is to take supplements and eat foods rich in the nutrient. While the body has a built-in mechanism for preventing vitamin D toxicity from the sun, going out unprotected can lead to skin cancer, sunburn and itchy rashes.

Diet

If you're on high doses of vitamin D and also eat a diet rich in the nutrient and are breaking out in skin rashes, it may not be the vitamin that's to blame. Rich dietary sources of the sunshine vitamin include salmon, sardines, egg yolk and fortified milk and cereal. Of these foods, at least three are on a list of the eight foods most likely to cause an allergic reaction. The Mayo Clinic reports that fish, eggs and milk are among a short list of foods that cause 90 percent of allergic reactions. Symptoms of a food allergy include hives, itching and skin rashes.