Dihydroxyacetone, the active ingredient in all sunless-tanning products, causes contact dermatitis in some users. Dihydroxyacetone is an FDA-approved sugar product that changes the color of the dead skin cells on the surface of the skin to give the individual a bronze tone. An allergic reaction to dihydroxyacetone or other ingredients in the product is usually the cause of an individual experiencing a rash and itching after using self-tanning products.
Dihydroxyacetone is a chemical the body creates in converting glucose to energy. When applied to the skin, it causes a stain that approximates a natural tan; the stain is easy to remove by exfoliating the skin. When people use self-tanners, the dihydroxyacetone levels in their urine do not increase, indicating the chemical is not absorbed into the body.
While sunless-tanning products are much safer than tanning in the sun, they do carry risks. In addition to the potential for a reaction to the product, they often give users a false sense of security. Sunless tans do not provide protection from the sun in the way that a natural tan does. After using a sunless-tanning product, people must use sunblock or stay out of the sun to avoid sunburn and skin damage.