CONTACT PATCH TESTING (Skin Allergy)

If you were advised by us that you are eligible for contact patch testing, please read this section. Note that you need to be seen and assessed by the allergist before you are deemed eligible for the test.

What is a contact patch test?
Patch testing is a tool used to identify potential triggers of allergy induced rashes (allergic contact dermatitis). This test identifies delayed-type allergic reactions which cannot be identified by common allergy skin prick or blood tests. An example would be nickel jewelry or allergens to cosmetics. Other examples include clothing, sunscreen, surgical implant material (such as hip replacements or metal rods), dental materials and rubber products. Anything that makes contact with your skin has the potential to cause allergic contact dermatitis.

You CANNOT be patch tested if the following applies to you:
- You are pregnant
- You are breast feeding
- You have significantly inflamed skin to your back: eczema, rashes, sun burn, psoriasis etc.
What is the difference between a contact patch test and the common allergy tests?
The common allergy test that you may have heard about is a skin test which applies either environmental allergens such as trees, grass or mold pollen or a particular food to your skin. The skin prick test evaluates for an IgE mediated reaction. It takes 15 minutes and can be done quickly in our office. That test evaluates for symptoms that are usually not skin related, such as a runny nose after pollen exposure or breathing difficulty after food exposure.

The contact patch test is a very different test. This test evaluates for a cell-mediated skin allergy or an irritant reaction that is a consequence of having an allergen make direct contact to your skin. Contact patch testing requires a total of 3-7 days and four appointments until the results are ready to be interpreted.
What is the benefit of having a contact patch test performed?
Contact Patch Testing is the only medical test that can identify if there is a particular substance that is causing you a skin allergy. It not only identifies the allergen, but importantly helps you avoid the allergen. For instance, if you are allergic to a certain metal or dental material, this test will help you avoid that particular product before you have surgery. If you are allergic to a particular component of a shampoo or make-up product, it can enable you to use products that do not contain that allergen.
What are the risks or discomforts of a contact patch test?
Contact patch testing does not result in any general systemic reaction, such as anaphylaxis. If you are allergic to any of the patches placed, you will develop a localized irritant reaction consisting of red, itchy skin the size of the patch placed (typical less than the size of a dime).

Unlike skin allergy testing, there are no needles or pricks involved in contact patch testing.

The discomfort with contact patch testing is firstly not being able to get your back wet for the time it takes to have the allergen read (2-7 days). In addition, patients occasionally find the irritation reaction - if they are allergic to any of the patches - uncomfortable.
How to I prepare for a contact patch test?
There are three appointments involved in this process. That does not include the qualifying appointment which is to obtain a history and to determine whether you qualify to contact patch testing.

The first contact patch test appointment is where we will apply anywhere from 1 to 5 sheets of allergen are placed on your back at the first appointment. Each sheet contains 10 allergens.

You will have to return to our clinic two more times after that. The second appointment is always 48 hours after the patch test was initially applied. At that appointment the patch tests are removed and the first read is performed.

The final appointment (third) occurs anywhere from 1 to 5 days after the patches have been removed. This is when the final read occurs and you and given a list of the allergens to which you were tested and what you may be positive to.

There are a number of important steps you need to take in order to prepare appropriately for this test:

Two weeks before the test:
- If you tan, do not go to any tanning salons
- Do not expose your back to the sun (such as sunbathing or swimming pools)
- If you are taking oral steroid medication such as prednisone, it needs to be discontinued two weeks before testing as it can interfere with the results. If you are taking oral steroids, you will need to talk to your prescribing doctor to see if there is anything else you can take instead of that medication.

One week before the test:
- Do not apply any lotions or creams to your back. This includes topical steroids or prescription creams.
- If you have back hair, shave your back. Applying the contact patch test strips over a hairy back can affect the results.

The day of your test:
- Wear loose cotton clothing. Do not wear any tight clothing that can interfere with the patches being applied (such as a bra if you are female).
- Do not wear your best clothes. We mark certain areas on your back with a skin approved medical marker. The marker may rub off on your clothes.
Describe the steps once I have the contact patch test strips applied.
The days you have patches applied:

The patches will need to remain on your back for two days.

- Keep your back dry during the time patch testing is applied as wet patches will invalidate the results. No showering. If you feel the need to wash yourself, do so with a flannel or a wet cloth. If the patches fall off, you will need to have the entire procedure repeated (and will need to pay the full contact patch test fee again as the material will need to again be prepared)
-Dr Hadi does not recommend you go to the gym to work out during that time. The moisture that you accumulate secondary to you sweating can loosen the contact patch adhesive.
- Wear loose cotton clothing during the night time. An old t-shirt is ideal.
-If a patch becomes loose, reattach it with medical adhesive. If it falls off, remove it and note the day and time it came off and call us.
- If you are feeling uncomfortable or itchy, you can take anti-allergy medication such as Benadryl or Reactine.
Why is there a fee for this test?
Not all medical services in Alberta are covered by Alberta Health. Contact Patch Test materials is one of these services that is not paid for by Alberta Health. As such, patients are required to pre-pay for the material to which they are tested.

Once we prepare the contact patch test material for you, the patch material needs to be applied to your back within a few hours as the volatile compounds degrade rapidly. It is therefore important that you attend your appointment. If you cancel your appointment less than 48 hours before your scheduled date, no refund will occur as your contact patch test material will already have been prepared and will consequently be discarded.

Should you wish to have contact patch testing performed at a later date, you will need to pre-pay the fee again as we will have to prepare another series for you.

Obviously for your benefit, please be certain that you can attend your contact patch test appointment prior to setting up a scheduled time with us.






Hours of Operation:
Monday 0800-1500
Tuesday 0800-1500
Wednesday 0800-1500
Thursday 0800-1500
Friday 0800-1200
Weekends and Holidays: closed

Address:
Allergy Physicians Calgary
5918 - 3rd St SW
Calgary T2H 0H8

Telephone:
403-ALLERGY (403-255-3749)
Facsimile:
1-833-816-5734
(Second fax line: 403-457-8237)


Drs. Hadi, Hinther and Almatrafi are medical sub-specialists and per Alberta Health regulations see patients via referral only. If you have an emergency, please call 9-1-1 or go to the nearest hospital. If you have an urgent or semi-urgent medical need, please see your primary care physician for evaluation or advice.

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