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Information on patch testing for common foods and contact allergens

Patch testing involves three appointments in our office, typically:

• Monday for Patch Application

• Wednesday for Patch Removal (48 hours later)
• Thursday for Patch Reading (72 hours later)

There may be an option of the final patch reading approximately 96 hours later from application versus the standard 72 hour.

Please plan 1-1.5 hours for the first appointment; subsequent appointments should not exceed 45 minutes.

Before you have a patch test done, you should:

1. Shower or bathe prior to your appointment as you will be unable to get the testing site wet for up to 96 hours after application of the patch.

2. Avoid the use of oral or topical steroids on the test area for 2 weeks prior to testing. Also oral steroid therapy (i.e. Prednisone) may interfere with results. Please notify our office if you are currently taking oral steroid therapy.

3 .If you are on inhaled steroids (i.e. Flovent puffers), please let us know.

4. Minimize sun exposure on the test area 3 weeks prior to testing.

5. DO NOT apply lotions, creams, or ointments to the test area before the test.

6. Your upper back must be free of body hair; this may require shaving. Please arrange the necessary shaving at home, or if not possible bring a shaver to your appointment.

7. Please notify our office if you have any appointments for imaging (MRI, etc) during your patch test appointments. Patch testing cannot be carried out if you are scheduled for imaging as the patch chambers contain metal.

During the test period, you should:

Keep the patch test area dry.  Avoid activities that cause perspiration, i.e. organized sports.

You may NOT take a bath or shower until after the patch is removed; however, you may sponge bathe around the patch test site.

Wear loose-fitting clothing. Also, wear dark clothing for the removal appointment

Call Dr. Ohayon’s office immediately at 905-777-0088 if the test site is severely burning or itching or if the patch test becomes loose. 

**Please note that the testing site where the patch has been applied will be uncomfortable. This discomfort is usually caused by the tape securing the patch**

It is recommended that you have a camera on hand in case of delayed reactions.  If photos are taken, please email them to us at Dr. Ohayon may ask that you return to the office to assess the testing site and mark out the area of concern.

If skin testing is also indicated at your patch testing appointment:

No antihistamines, over-the-counter cough, cold, or flu medications including Gravol, (which contains a decongestant) for five (5) full days prior to the visit.

Asthma puffers, Allergy nasal Steroid sprays and Eczema creams MAY BE CONTINUED.

If you are on beta-blocker therapy,  you will require permission to discontinue their beta-blocker for four (4) days prior to this appointment. **ALLERGY TESTING WILL NOT BE DONE WHILE ON A BETA-BLOCKER** If you cannot tolerate discontinuing your beta blocker prior to the appointment, then we will see you in consultation first. 

Please have the family take photos and maintain diary of these episodes. 

*The first appointment will be at least 1 –1 1/2 hours.

Usage Patch Test for Contact Dermatitis

It may be possible that a direct application of a suspected allergen on your back is indicated from cream/lotions you are currently using in your home.  If you suspect that this may be the case, please inform our team.  Dr. Ohayon and his staff will ask you to bring the lotions,  creams, and/or make-up materials that you use on a regular basis for application, similar to your patch testing application.  This is known as a “usage test”.

Food Patch Testing for Delayed Food Allergies:
**Unless you were specifically notified that you will be undergoing food patch testing, please follow the contact dermatitis general preparation.**

You will be asked to bring samples of foods that may be causing a delayed allergic food reaction, i.e. eosinophilic esophagitis or enteritis:

1.You will need to keep a diary of foods that you eat in your diet.

2. Please bring at least 30 of the most common foods in your diet.

3. The foods MUST be in their purest form and not mixed with any other ingredients: i.e. not a cereal, cookie, dish. The major proteins are needed to test for food allergy on atopy patch testing, i.e. wheat, oats, rice for cereal and, if there are nuts in cereal, nuts separately, etc.

4. If the food is a fluid, such as milk, soy milk, egg white/yolk, please bring at least 1 oz (30 ml) of the liquid food product.

5. If the food is a solid, it MUST be pureed in a blender and brought to our clinic. Please

ensure that the blender utensil is washed in between blending more than 1 food, i.e. fruits,

meats, vegetables.

6. If the food is available in powder form, i.e. wheat flour or rice flour, please bring 1 ounce or 30 g of the powder.

7. Each of the foods must be clearly labeled and placed in separate sealed sandwich bags.

Preferably, the samples must be brought to our office at least the

Friday prior to your first scheduled appointment so the patch may be prepared in advance. Please contact our office at 905-777-0088 to arrange the drop-off time to ensure we are able to receive your samples or if you have any questions about the patch testing process.

Cancellations must be made more than 24 hours prior to the appointment time. All missed appointments will be subject to a fee.

We Offer Patch Testing For:

Patch Testing for Contact

Contact Dermatitis
Delayed Food Allergies (i.e. eosinophilic esophagitis)

Click here for information on our available common contact allergens.

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