Patch testing is generally done to see whether a particular substance is causing allergic skin irritation (contact dermatitis). Patch tests can detect delayed allergic reactions, which can take several days to develop.

Patch tests don’t use needles. Instead, allergens are applied to patches, which are then placed on your skin. During a patch test, the skin on your back may be exposed to up to 36 extracts of substances that can cause contact dermatitis. These can include latex, medications, fragrances, preservatives, hair dyes, chemicals and resins. Patch tests are performed over a 4 day period with most results being seen in 72 hours.

During this time, you should avoid bathing and activities that cause heavy sweating. The patches are removed when you return to Affiliated Dermatology. Irritated skin at the patch site may indicate an allergy. Affiliated Dermatology also offers a skin test on the back with 80 antigens that provides results within 60 minutes.


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For more information or to schedule an appointment at one of our several dermatology offices in Arizona, please contact us by calling (480) 556-0446, requesting your appointment online, or by leaving us a message on our contact form.