Common Causes of Allergic Contact Dermatitis

Although most people are aware of poison ivy and oak as causes of blistering rashes, many other substances found in the home or workplace can have the same effect. Typical among them are metals (nickel in particular), cosmetics, chemicals, dyes, the tanning agent in leather (which may cause allergies to shoes, for example), perfumes, the sizing chemicals in fabrics and the ingredients in topical creams and ointments.

Although a contact rash looks the same no matter what triggered it, with red, itchy, swollen areas that blister, weep and crust, the location of the rash gives clues to what may have caused the reaction.

A pattern behind the ears, on the sides of the neck, the pulse points on the wrist and bend of the elbow suggests an allergy to perfume. An outbreak encircling the neck or wrist suggests an allergy to metals in jewelry. Rashes on the hands suggest allergy to cleaning solutions or food substances. With common sense and a little detective work, it is possible in most instances to track down probable causes of the problem. Once a list of reasonable suspects is made, an allergist or dermatologist can use patch testing to narrow the field. In a patch test, the allergist or dermatologist tapes small cotton pads containing test amounts of suspected allergens onto the skin of the back. After 48 hours the pads are removed and the degree of reaction to each allergen is noted.

Identifying an allergen allows you to avoid it and prevent the contact rash from recurring. Following is a list of some substances that commonly cause sensitivities.

• adhesives
• cleansers
• clothing (rabbit hair, elastic waistbands)
• cosmetics
• detergents
• dyes (hair, leather, cloth)
• fragrances
• leather (tanning agents)
• ointments or creams containing medication such as neomycin or bacitracin
• metal jewelry
• paints or varnishes
• preservatives such as formaldehyde that are used in sunscreens, antifungals, over-the-counter steroids and other lotions
• rubber products latex, elastic bonds in clothing, shoes, gloves
• shampoo
• shoes containing leather tanning agents or rubber chemicals
• soaps
• sunscreen
• toothpaste

Last Updated: 9/26/2002
The Johns Hopkins University 1996-2003.  All rights reserved.  This information is not intended to provide advice on personal medical matters, nor is it intended to be a substitute for consultation.