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Patch testing for skin allergies


Patch testing is used to identify allergens that may be causing outbreaks of contact dermatitis – a localized rash or irritation of the skin where allergen(s) came in contact. Modern Dermatology is pleased to offer the North American 80 Comprehensive Series (NAC 80), which is the preferred series of the North American Contact Dermatitis Group.

Patch tests are used in patients with dermatitis to find out whether their skin condition may be caused by, or aggravated by, a contact allergy. Patch tests are not the same as skin prick tests, which are used to diagnose hay fever allergy (house dust mite, grass pollens and cat dander) or other environmental or food allergies. Skin prick tests have very limited value for patients with skin rashes. Identifying allergens, so they can be avoided, is the only way to prevent outbreaks of contact dermatitis.

Your first appointment is the longest and may last up to 90 minutes. Tiny quantities of 80 antigens will be placed on your back in thin chambers. Tape will be applied over the top of the chambers to assure proper occlusion. These chambers will remain on your back for 48 hours. It is important to keep the area dry and free of all products during the entire testing phase, which is approximately 4-5 days. 

When you return in 48 hours, the tape and the chambers will be removed so we can examine the area being tested. The back is marked with a black felt tip pen to identify the test sites. You will return again in another 24-72 hours for a final evaluation.

For the most reliable patch testing, antihistamines and steroids (both topical and systemic) should be avoided for fourteen days prior to application.