Cosmetic Allergy and Contact Dermatitis

Contact dermatitis is an itchy, blistering skin rash typically caused by the direct contact of a substance with the skin. There are two types of contact dermatitis: irritant and allergic. It's often difficult to differentiate between the two types but is not usually important to make the distinction.

Contact dermatitis results in 5.7 million doctor visits each year in the United States, and all ages are affected. Females are slightly more commonly affected than males, and teenagers and middle-aged adults seem to be the most common age groups affected.

Cosmetic-Induced Contact Dermatitis

Cosmetic-induced contact dermatitis is common, since people may apply numerous chemicals to their skin, hair, and scalp daily. Typically, the rash will occur on the skin where the cosmetic was applied, such as under the arm if the irritant is an antiperspirant, but sometimes the rash will occur on another part of the body (for example, reactions to nail polish may first cause an eyelid rash as a result of touching the eyelid). It's possible for an allergy to a substance to develop even after years of using the cosmetic without previous problems.

Fragrances

Contact dermatitis to fragrances is one of the most common causes of contact dermatitis. Rashes can appear on the neck in a pattern consistent with spraying perfume on the area, such as the face and neck. Avoiding fragrances can be difficult, and use of products labeled “unscented” can be misleading, as a masking fragrance may be added. It is better to use products labeled as “fragrance-free,” which are typically tolerated by people with fragrance-induced contact dermatitis.

Fragrances may also be present in perfumes, shampoos, conditioners, cosmetics, moisturizers, laundry detergents, and fabric softeners. Given the large number of substances that may contain fragrances, as well as the poor labeling of these products as containing fragrances, you may need to try avoiding these products to try to remove the trigger of the rash.

Preservatives

Allergy to various preservatives, found in many cosmetics and personal hygiene products, may also cause contact dermatitis. Many of these preservatives contain formaldehyde, including quaternium-15. Other non-formaldehyde containing preservatives include parabens, thimerosal, and isothiazolinone.

Hair Products

Hair products are another common cause of contact dermatitis and are the second most common form of cosmetic allergy. Common chemicals include phenylenediamine in hair dyes, Cocamidopropyl betaine in shampoos and bath products, and glyceryl thioglycolate in permanent wave solution. It is very common for reactions to hair-care products to cause contact dermatitis on the face, eyelids, neck, and back before affecting the scalp.

Fingernail Coatings

Reactions to acrylic coatings on fingernails are a common cause of contact dermatitis on the fingers, as well as on the face and eyelids. Many people who use cosmetics on their fingernails (artificial nails or coatings on natural nails) may touch their face and eyelids with their nails, often without realizing it. Common chemicals include acrylates and formaldehyde-based resins.

These chemicals are frequently used in professional nail salons, but can also be present in nail polish, especially those claiming to be nail strengtheners and containing topcoats. Always check the ingredient list on the bottle before purchasing any nail polish or coating if you experience contact dermatitis to acrylates or formaldehyde resins.

The location of the contact dermatitis can help in the evaluation for causes.