Award winning dermatology service, with over 20 years of experience

Short waiting lists, on some occasions offering same week appointments

Safe environment, in Care Quality Commission approved facilities



At Canterbury Skin and Laser Clinics, our patch testing facility is a specialised unit designed to identify the sources of allergic contact reactions that may be affecting your skin. In addition to patch testing, we offer comprehensive blood allergy testing to detect allergic components that may be contributing to your skin issues. The substances used in these tests are commonly found in everyday products and can cause skin allergies. Typical allergens include metals, perfumes, rubber, glues and preservatives found in various toiletries. Please note that patch testing does not identify allergies related to diet, hay fever or asthma.


Patch testing is performed to identify substances that may be causing or aggravating your rash through contact with your skin.

During patch testing, sticky patches are applied to your back or sometimes to other non-affected areas of skin like your arms or legs. These patches have small compartments that hold common household chemicals pressed tightly against your skin. Examples include fragrances, colourings, preservatives found in creams, hair dyes and metals. These are all common chemicals found in everyday life and none are toxic. Patch tests can check for 20 to 70 allergens at one time.

The testing process requires three visits to the clinic over five or six days:
1. The patches are applied and the areas are marked with ink.
2. After 48 hours, the patches are removed, readings are taken, and the areas are re-marked with ink.
3. A final reading is taken 48 to 72 hours later.

This process helps identify any allergens that may be affecting your skin condition.

Your First Patch Test Visit

Before your first patch test visit, ensure your back is clean, free of hair and not covered in moisturisers.

During the visit, patches will be applied to your upper back, and possibly your arms or thighs. These patches are small discs on hypoallergenic tape and the skin will be marked with ink. The patches need to remain in place for 48 hours. If a patch becomes loose, please tape it back down. It is normal to experience itching at the patch test sites and you may find your back movements slightly restricted. If you are allergic to one or more of the substances, it will show up on your back even if the rash is elsewhere on your body. Once the patch tests have been applied, keep your back dry from water and sweat until after the final appointment.

Your Second Patch Test Visit

During your second patch test visit, the patches will be removed from your back after two days, and we will check for any early positive reactions. Your back will be marked with ink and we may leave a strip of tape to help identify any further reactions at your final appointment. It is important to keep your back dry, as the markings need to remain visible on your skin.

Your Third Patch Test Visit

The final patch test reading will take place between 5 and 7 days after the initial application. During this visit, your consultant will discuss the results with you and provide detailed information about any substances you have reacted to. This information will help you avoid contact with these allergens in the future.


Maintaining dryness is crucial for accurate patch testing. Moisture can dissolve the allergens from their chambers, making the results difficult to interpret.

For the entire 4 to 5-day testing period, while the patch tests and ink markings are on your skin, please adhere to the following guidelines:

  • Get the patches or markings wet in the bath or shower
  • Work up a sweat by exercising too hard
  • Go swimming
  • Wear pale or valuable clothing as the ink may stain it
  • Expose yourself to sunlight
  • Take immunosuppressive medications (if you are already taking these, patch testing may not be possible as the results will be suppressed)
If the area becomes itchy, try not to scratch.

  • Use the shower cautiously and sponge wash yourself while keeping the patches/markings out of the water flow
  • Shower on the morning before your patch test, as you won’t be able to have a proper shower for at least the next 96 hours
  • Enjoy a break from exercise or sport that causes you to sweat
  • If you notice a patch coming loose, try to tape it down yourself
  • Contact the clinic if you have any questions or concerns
  • Remember, these restrictions and recommendations need to cover the entire period from the first visit right through to the last, or the results may be invalidated

Remember, these restrictions and recommendations apply from the first visit through to the last to ensure valid results.
If you have a positive allergy, the most common side effect is itching. Occasionally, you might also experience an irritant reaction under the tape, which can be itchy as well. Other potential side effects include:
  • Reactions that become red, swollen or even blistered.
  • Strong positive allergies may cause persistent reactions that can take a few weeks to disappear.
  • Eczema may flare up in response to a positive patch test.
  • Inflammation can cause pigment changes, which may lighten or darken the skin. These changes sometimes last for a few months but are rarely permanent.
Patch testing is not advisable if you:
• Are pregnant or breastfeeding
• Have extensive eczema on your back
• Have been exposed to the sun or have used a sun bed over the previous 2 weeks
• Have recently applied an artificial tan
• Are using moderate or high dose oral steroids

It is not possible to apply test patches if the skin on your back is scratched, sunburned, has a rash or has excessive hair growth. If you have excessive hair on your back, please shave the area before your appointment.

Additionally, avoid using antihistamines for 48 hours before and during the patch testing period, as this could reduce any visible reaction to the allergens.


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What our Customers Say


Here at Kent’s leading private skin and laser clinic, our experts are specialists in all aspects of dermatology, skin cancer, anti-ageing and beauty treatments. We are one of the few skin clinics in the UK where all medical consultations and treatments are provided by specialist doctors with Dermatology experience and laser training.

Canterbury Skin and Laser Clinic is regulated by the Care Quality Commission, ensuring the best level of treatment is provided to you in a safe environment. Our Clinical Lead Dr Mark Hudson-Peacock is a member of the British Association of Dermatologists, the British Laser Medical Association, the British Hair and Nail Society, the European Academy of Dermatology and Venereology and is certified by the Consulting Room. We have won many awards including the WhatClinic Patient Service Award in 2019 and the ghp Healthcare and Pharmaceutical Awards 2019.


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