Skin Rashes Caused by Vitamin Deficiency

You no doubt have heard that vitamins are good for you, but you may not know that vitamins are important for healthy skin. Although vitamins are necessary for many body functions, the human body is unable to make most vitamins. Because of this, deficiencies may occur when adequate amounts of vitamins are not obtained from the environment, usually because of a poor diet or a disorder interfering with the absorption of food nutrients in the digestive tract.

As rashes and skin changes are easy to see, sometimes they are the first sign of a vitamin deficiency. See your doctor if you notice any of the changes described below or if there is any other reason that you think you may have a vitamin deficiency.

Vitamin C is an antioxidant and plays an essential role in many body functions, including the production of an important protein called collagen. Fruits and vegetables are the main sources of vitamin C. As healthy skin contains a large amount of collagen, vitamin C deficiency -- also known as scurvy -- causes changes in the skin. Bruising is common with scurvy. The skin can be rough and tear easily. Skin hairs may have a corkscrew appearance and bleeding can occur around the base of each hair.

Niacin is primarily involved in energy production within cells. Inadequate dietary consumption, as well as some medications, may cause niacin deficiency -- also known as pellagra. Niacin deficiency skin changes typically begin as inflammation in sun-exposed areas, as the skin become unusually sensitive to ultraviolet rays from the sun. The skin appears red, painful and itchy, like a sunburn.

With time, the skin becomes swollen and blisters develop. Once the blisters burst, the skin becomes crusted with brown scales. These areas eventually become thickened and darkly pigmented. The backs of the hands are most commonly affected. The face, neck and other parts of the arms and legs are also frequently involved.

Riboflavin is another energy-producing B vitamin. Riboflavin deficiency causes inflammation of the skin, particularly in the nose area, forehead, cheeks and behind the ears. It also commonly affects the genital region and, according to an article in the October 2016 issue of the "Cleveland Clinic Journal of Medicine," inflammation in this area is the first sign of riboflavin deficiency in many people. Riboflavin deficiency tends to affect the genital region more severely in men than in women.

Vitamin B6 is required for normal function of over 100 enzymes within the body, according to the 2016 "Cleveland Clinic Journal of Medicine" article. Deficiency of vitamin B6 is rare except in people with alcoholism or taking certain medications that inactivate it.

Vitamin B6 deficiency can cause seborrheic dermatitis -- reddened patches of skin with white or yellowish scales that flake off. These occur most commonly on the face, scalp, neck, shoulders, buttocks and perineum. Vitamin B6 deficiency may also produce angular stomatitis -- inflammation with redness and swelling at the corners of the mouth. Because vitamin B6 is necessary for the production of niacin, vitamin B6 deficiency can also lead to niacin deficiency skin changes.

Vitamin B12 is necessary for the production of DNA, a process that occurs in every cell. Not surprisingly, vitamin B12 deficiency has a number of effects in the body. The most common skin changes are areas of darkened skin -- hyperpigmentation -- or lightened skin -- hypopigmentation. Hyperpigmentation most commonly occurs on the backs of the hands and tops of the feet, according to an April 2008 article in "Canadian Family Physician." Vitamin B12 deficiency may also produce angular stomatitis.

Biotin plays important roles in the metabolism of carbohydrates and fats. Biotin deficiency is extremely rare because the body does not require a lot of biotin, the vitamin is available in a large number of foods and it can be produced by bacteria living in the intestines. Deficiency of biotin can cause seborrheic dermatitis. This rash tends to appear first around the mouth, nose and eyes. The skin may also be unusually susceptible to fungal infections, according to a January 2015 article in "Podiatry Today."

Vitamin A is actually a group of very similar vitamins, including retinol, retinoic acid and beta-carotene. Vitamin A is a fat-soluble vitamin, which means that it is stored in the body for future use. Because of this, vitamin A deficiency is uncommon. Vitamin A is necessary for proper formation of the outer layer of the skin. With vitamin A deficiency, the skin becomes dry, itchy and scaling. Severe deficiency can cause deep cracks and fissures in the skin.

Vitamin K is necessary for the production of coagulation factors -- proteins in the blood that produce blood clots. With vitamin K deficiency, the blood does not clot normally. This can lead to easy bruising, as well as prolonged bleeding from cuts in the skin.

Reviewed and revised by Mary D. Daley, M.D.