Allergic contact dermatitis presents as an itchy pink rash. Patch testing helps identify the chemical that could be causing it and requires three office visits.  Do not apply any corticosteroid creams to your back for two weeks prior to your patch test placement.

 

Office visit #1

     The dermatologist tapes eight paper patches onto your back. These patches contain eighty different chemicals that commonly cause contact dermatitis. Wear loose fitting clothing on this day because tight fitting clothes may rub the patches off your back. Also, do not apply any creams to your back on this day because creams will prevent the patches from sticking to your skin.

     You may develop itching under the patches, which may be a sign that you are allergic to one of the test chemicals. Do not scratch the patches since this can shift them  and make interpretation of results difficult.     

     Keep your back dry at home. Getting your back wet may cause the patches to fall off. Therefore, instead of showering, keep clean by washing with a sponge. Also, avoid heavy lifting, excessive bending, and physical and aerobic exercises that could cause sweating and detachment of the patches.

     Wear loose fitting clothing at home and a t-shirt in bed to prevent the patches from peeling off. If the patches start peeling off, pressure the adhesive back onto your skin or apply additional tape. 

 

Office visit #2

     Two days later the dermatologist removes your patches and notes all skin reactions.  He or she then applies a felt-tipped pen to the skin to specify exactly where the patches were initially placed.  Wear an old t-shirt on this day because the marking pen could wipe off your back onto clothing.  When you go home, avoid showering and exercising because moisture on your back could wipe off the marking pen.  Wash with a sponge as before.

 

Office visit #3

     Two to five days later, the dermatologist examines your back for any delayed skin reactions.  The doctor then discusses what is causing your rash and recommends using or avoiding specific products, depending on the results.