Patch testing is useful for evaluation of allergic contact dermatitis or skin allergies. Allergic contact dermatitis occurs when an individual's immune system reacts to a specific allergen, such as a rash after touching poison ivy.
Allergic contact dermatitis may be the primary cause of a person's eczema, or it may complicate other types of eczema, making treatment more difficult. Patch testing can identify whether a substance that comes into contact with the skin is causing eczema or inflammation of the skin. Once an allergen has been identified through patch testing, avoiding the offending substance will usually result in clearance of the rash. Patch tests are not the same as skin prick or scratch tests, which are used to diagnose hay fever or food allergies. Skin prick tests have limited value for evaluating eczema.
The patch testing process involves the application of small amounts of commonly reacting materials to your back under adhesive tape that are left in place for 48 to 72 hours.
Photopatch testing is useful for evaluation of photoallergic contact dermatitis. This rare type of contact dermatitis occurs when an individual's immune system reacts to a specific allergen that is modified by sunlight.
Frequently Asked Questions
- Is patch testing going to hurt?
Patch testing is a non-invasive, non-painful, in-office procedure. Patch chambers loaded with allergens are placed on the skin, similar to stickers on a surface. Some patients have reported mild discomfort from having the patches taped onto their backs. Staying cool and minimizing heat/sweat are key to ensuring swift, efficient removal of patches. We apply hypoallergenic tape on top of patches to help prevent shifting or peeling. Any upper body movement restrictions are lifted once the hypoallergenic tape and patches are removed.
- Is there anything I should temporarily change for my daily routine?
- No topical medications on your back for at least 7 days prior to patch placement.
- No oral steroid for at least 28 consecutive days prior to patch testing
- Avoid excessive, direct sun exposure on your skin for at least 4 weeks prior to patch placement.
- Avoid getting your back wet, whether it be from a rainy day, festivities, significantly physical activity, or a shower. Areas not covered by patch chambers must not get wet or risk allergen runoff to other areas of the skin, which would interfere with accurate test results and result in shifting/peeling of patches, etc, to reduce the risk of allergy re-testing.
- Do I need to stop using my oral antihistamines (allergy medications)?
It is okay to use your oral antihistamines when necessary as recommended by a medical professional.
- Do I need to stop using my inhaler for my asthma? It’s a steroid-based medication.
It is okay to use your steroid-based inhalers when necessary as recommended by a medical professional.
- Do you patch test pediatric patients?
Yes. As long as we are able to make a strong enough case supporting pursuit of patch testing. Please contact our team to schedule an appointment.
- Can I skip the consultation and be scheduled for direct patch testing?
We strongly recommend all patients hold a consultation prior to scheduling direct patch testing. The consultation gives us the opportunity to review important past medical history and set realistic expectations for going through the procedure.
- Is patch testing the same as prick testing? I was screened for allergies with my allergist.
Patch tests are not the same as skin prick or scratch tests, which are used to diagnose hay fever or food allergies. Patch tests can screen for allergies found in personal skin products, clothing, dyes, etc.
Make an Appointment
Please call our main dermatology line at 202-741-2600, and ask to speak with an office patch scheduler. They can assist with scheduling an appointment for a patch consultation with Dr. Jonathan Silverberg.