Does Vitamin D Deficiency Cause A Rash?

Doctors classify vitamin D as a fat-soluble vitamin because your body can store it in the liver and fat cells. Although you need vitamin D to live, doctors do not consider vitamin D an essential vitamin because your skin cells produce the majority of vitamin D when exposed to the ultraviolet rays of the sun. According to research published in the September 2003 issue of “Rheumatology," food only provides approximately 20 percent of your vitamin D needs. Although your skin plays a major role in regulating vitamin D levels, a vitamin D deficiency does not cause a skin rash. Too much vitamin D, however, may cause skin rash.

Deficiency

A vitamin D deficiency can occur due to limited sun exposure, inadequate intake of dietary vitamin D, inhibited absorption and kidney dysfunction that inhibits the conversion of pre-vitamin D into active vitamin D-3. Because vitamin D promotes calcium absorption and regulates levels of calcium and phosphorus – the two minerals needed to build and maintain strong bones – in the blood, a vitamin D deficiency affects the health of your bones.

Deficiency Conditions

In children, a vitamin D deficiency causes rickets, a medical condition characterized by soft, weak bones. The lack of vitamin D, and therefore calcium, causes delayed growth, muscle weakness, bone pain and skeletal deformities such as bowed legs, curved spine and breastbone projections. In adults a vitamin D deficiency causes osteomalacia. Although adult bones do not grow, they do undergo a continued process known as bone remodeling in which cells break down old bone material and use calcium and phosphorus to build new bone. Osteomalacia causes bones to become soft, which causes dull aching bone pain and muscle weakness.

Toxity

As a fat-soluble vitamin, vitamin D can be stored in your body. This means that it can build up into toxic levels. Symptoms of vitamin D toxicity include nausea, diarrhea, weight loss, headaches and skin rash. Your body produces the majority of vitamin D in response to sun exposure, but excessive sun exposure does not cause vitamin D toxicity. Sustained heat from the sun degrades the vitamin D as it forms, therefore regulating vitamin D levels. Since food provides only small amounts of vitamin D, excessive intake in food is also unlikely. The cause of vitamin D toxicity is consuming large amounts of vitamin D in dietary supplements.

Recommended Levels

To avoid a vitamin D deficiency and toxicity, the U.S. Department of Agriculture's Dietary Guidelines for Americans recommends that adults consume 600 international units, or 15 micrograms, of vitamin D per day. Since adults over the age of 70 need additional calcium to keep their bones healthy, they should consume 800 IUs, or 20 micrograms, of vitamin D per day. Intakes of more than 1,000 IUs, or 100 micrograms, per day increase the risk for vitamin D toxicity and associated skin rash.