Patient Handouts : Patch Test

Patch Test

Patch testing is done to test for a skin allergy to substances in the environment.

Your skin can become allergic to nearly anything, but there are a relatively small number of compounds to which people commonly become allergic.

The test takes several days!

On the first day, several test strips are applied to the skin, usually the back.

For the next two days you must not get this area wet! Getting the strips wet will cause them to lift off the skin, invalidating the test. This means you cannot take a shower for the first two days of the test.

Two days after the test strips are applied, you return to the office to have them removed, and the area covered by the strips is evaluated for any allergic reaction.

Allergic reactions commonly take 2-4 days before they can be seen, so you have to come back a third time, usually 4 days after the strips were applied.

Between the second and fourth day you ARE allowed to shower, but you should not apply soap to the back, and you should not immerse your back in water.