By Gary M. White, MD

See also Contact Allergen Database,, allergic contact dermatitis, and patch testing. A recent study showed that 3700 allergens have been documented to cause allergic contact dermatitis.   The most common reactions are to nickel, thimerosal, cobalt, fragrance, neomycin, and balsam of Peru.

Balsam of Peru

A natural ingredient commonly found in fragrances, perfumes, and certain foods. It may cross-react with benzocaine. There is a balsam of Peru-free diet [JAAD 2001;45;377 and 470].


A topical anesthetic.



Carba Mix

An allergen found in rubber.


Sodium hypochlorite may rarely cause allergic contact dermatitis [Cont Derm 1999;41;347]. It may present in patients who clean with bleaching agents or in people swimming in heavily chlorinated pools. Rarely, contact urticaria may develop.

Cinnamaldehyde Cinnamyl Alcohol

Commonly found in toothpaste, cinnamon flavor, and fragrance.


AKA rosin. Comes from the sap of trees. Newspaper-hand eczema [BJD 1992;126;161-5.]

Corticosteroid Allergen Groups

Corticosteroid Allergenicity


Detergents are only very rarely a cause of contact dermatitis [JAAD 2002;46;200].


Allergy after bleaching. See elastic.

Epoxy Resin

Two-part glues.


A stabilizer in some topical medications. May cross-react with meclizine, tripelennamine, or hydroxyzine.

Toluenesulfonamide-Formaldehyde Resin

Found in fingernail polish. The contact dermatitis may persist from scratching with fingernail-polished fingers.


See formaldehyde.
Various industrial and commercial products.

Imidazolidinyl Urea

A preservative. AKA Germall 115.


AKA wool wax alcohol or wool alcohol. Is found in many topical products.


Latex gloves, balloons, many stretchy items, and some foods.


An allergen found in rubber.


Methylisothiazolinone is a preservative. Common in many OTC products including baby wipes.


A topical antimicrobial agent.


A metal. See nickel.
Allergic Contact Dermatitis to Nickel in Glasses Allergic Contact Dermatitis to Nickel in Glasses


A preservative.


Black hair dye.
Allergic Contact Dermatitis to paraphenylenediamine in hair dye

Potassium Dichromate

Causes cement dermatitis.


A preservative. AKA Dowicil 200.


Poison ivy and oak.
Allergic Contact Dermatitis to Rhus on the Penis

Systemic Contact Dermatitis

Systemic contact dermatitis

Tea Tree Oil

Tea tree (Melaleuca alternifolia) oil may cause allergic contact sensitivity. It may also cause airborne allergic contact dermatitis [Contact Dermatitis 1996;35;304].

Textile Dye Dermatitis

JAAD 1995;32;631


AKA Merthiolate. In many topical products.

Thiuram Mix

A rubber allergen.

Topical Corticosteroid

See here

Unna Boot

Allergy to an Unna boot may rarely occur. Paraben included as a preservative is the most common cause. Some Unna boot products are preservative-free. JAAD 1995;33;906




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