Allergic contact dermatitis is a delayed hypersensitivity reaction that involves interaction of allergens and antibodies. The location of the rash can give important clues to the type of allergen causing the rash. The following lists give common allergens that cause allergic contact dermatitis grouped by location of the rash.
Scalp and Ears
- Shampoos
- Hair dyes
- Topical medications
- Metal earrings
- Eyeglasses
- Rubber ear plugs
Face
- Cosmetics - preservatives, emulsifiers, fragrances
- Acne medications - benzoyl peroxide, Retin-A
- Aftershave lotions
- Respirators, masks, aerosolized mists (machinists), volatile organic substances
- Chemicals applied to the scalp can spread to the face, ears, and neck - the scalp may not be involved because it is more resistant
- Airborne allergens such as poison ivy from burning leaves or ragweed
- Sunscreen ingredients such as oxybenzone and benzophenone No. 3
Eyelids
- Nail polish
- Cosmetics
- Contact lens solution
- Metal eyelash curlers
- Rubber makeup sponges
- Goggles
Neck
- Necklaces especially made of metals or exotic woods
- Airborne allergens such as ragweed
- Perfumes
- Aftershave lotions
- Cosmetics
- Textiles dyes or formaldehyde resins in clothing
Trunk
- Textiles especially if the rash does not involve the armpits or areas covered by undergarments
- Azo-aniline dyes found in colored clothing
- Urea formaldehyde resins found in wrinkle-resistant clothing
- Rubber allergens in elasticized waist bands or spandex bras
- Fragrances
- Preservatives in moisturizing lotions
- Topical medications
- Sunscreens
- Poison ivy
- Plants
- Metal belt buckles
Arms
- Same as hands
- Watch and watchband
- Soap
- Moisturizers
Fingertips
- Glue
- Disinfectants
Armpits
- Deodorants
- Clothing
Hands
- Soaps and detergents
- Foods
- Spices
- Poison ivy
- Industrial solvents and oils
- Cement
- Metal
- Topical medications
- Rubber gloves
Genitals
- Poison ivy - transferred by hand
- Rubber condom
- Diaphragms
- Pessaries
Anal Region
- Hemorrhoid preparations containing benzocaine or nupercaine
Lower Legs
- Topical medications
- Moisturizers containing fragrances or preservatives
