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Private Consultant Dermatologist
Specialist Services

Patch Testing Service

Patch Testing Service

We are delighted to announce that the Harley Street dermatology clinic has now opened its new patch testing facility. This is a specialist unit designed to ascertain if there is an allergic contact cause for your skin disease

In addition to patch testing, we can offer a full spectrum of blood allergy testing to see if there is an allergic component driving your skin disease

The new unit is run by our brand-new team of highly qualified dermatology specialist nurses and physicians assistant with many years of cumulative experience in providing patch tests for skin patients.

Our clinic is very happy to see any patient who has been referred by a consultant dermatologist (UK registered). If you have not seen a dermatologist and worried about contact allergy, then please book to see one of our consultants and we can facilitate your testing, investigation and treatment.

Remember, there is currently no test on the market other than a patch test that is able to identify a contact allergy. Blood tests are available for allergies, but these tend to be to identify inhaled, airborne or ingested allergens, not contact allergens.

Patch Testing Service

What is patch testing?

Patch testing is undertaken to try and identify if there are any substances which are causing or aggravating your rash by coming into contact with your skin

Patch testing involves having sticky patches stuck to your back (or sometimes to other areas of non-affected skin like arms or legs). Underneath the patches, small compartments hold common household chemicals pressed tightly against your skin. Examples of these include fragrances, colouring, preservatives found in creams, hair dye, metals et cetera. These are all common chemicals found in every day life and none is toxic

Patch test can check for between 20 and 70 allergens at any one time.

The testing requires THREE visits to the clinic over a five or six day period:

  • the patches are applied and the areas marked with ink.
  • 48 hours later the patches are removed, readings taken and the areas further re-marked with ink
  • A further 48 to 72 hours later, final reading is undertaken

Any fees charged for patch tests are inclusive of all visit and patch testing, but will not include a follow-up visit with your consultant should this be necessary If any relevant allergens are identified that might be contributing to your skin condition, these will be discussed and information leaflets given to you. Hopefully avoidance of the allergens will result in a great improvement in your rash.

Sometimes patch tests can be negative, and a contact allergy excluded.

"Dos and don’ts" during patch testing

Keeping the patches dry is the most important aspect of accurate patch testing. Water or moisture of any description will often cause the allergens to dissolve out of their chambers and often make results difficult to interpret

For the whole 4 to 5 day period whilst the patch tests and ink markings are on your skin:


  • Get the patches or markings wet in the bath or shower
  • Work up a sweat by exercising too hard
  • Get the patches wet by swimming
  • Wear pale or valuable clothing as the ink may stain it
  • Expose yourself to sunlight

Take immunosuppressive medications (If you already taking these, patch testing is not likely possible as the results will be suppressed)

If the area becomes itchy, try not to scratch


Use the shower cautiously and attempt to sponge wash yourself whilst keeping the patches/markings out of the water flow

Shower on the morning before your patch test (as he won’t be able to have a proper shower for at least a further 96 hours)

Enjoy a holiday from exercise or sport that causes you to sweat

If you notice a patch coming away, try to tape it down yourself

Contact the clinic if you have 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

What side-effects may occur?

If you have a positive allergy, the biggest side-effect people suffer with is itching! Sometimes one can also get an irritant reaction under the tape and this is also itchy

  • Occasionally reactions can become red, swollen or even blistered
  • In strong positive allergies persistent reactions may occur which take a few weeks to disappear
  • Eczema may flare up in the presence of positive patch test
  • Inflammation can cause pigment change which may lighten or darken and sometimes lasts for a few months but is rarely permanent


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