Patch Testing Information

What is a Patch Test?

Skin Patch Testing is one of a number of allergy tests that can be carried out by your Dermatologist to find out whether you have any allergies to any common substances that your skin comes into contact with. Dr Palamaras will normally test you with the British Standard Patch Test Series (BSS) which contains around 40 standard substances that anyone’s skin might come into contact with in everyday living. In addition, after Dr Palamaras has taken your medical history and examined your skin, he might feel that you need to be tested to one or several other additional Patch Test Series. The kinds of substances that we test on your skin in the BSS include: metals, rubbers, perfumes, preservatives and plants.

Patch testing
Figure 1: Patch testing

How can I be referred for Patch Testing?

Patients are usually referred to Dr Palamaras by their GP because they have problems with their skin. Alternatively, you may wish to self-refer yourself and book an appointment directly to see Dr Palamaras by contacting his secretary or the clinic. After taking your history and examining your skin, Dr Palamaras might feel that there is a possibility that your have an allergy to something that you are coming into physical contact with. Dr Palamaras will then arrange a Patch Test for you accordingly.

What will happen at the Patch Test Clinic?

The Patch Tests are applied over the course of one week usually on a Tuesday, Thursday and Friday; there are three appointments in total.

The first appointment is on a Tuesday: At this appointment Dr Palamaras will see you and ask you about your skin problems. He will then decide which Patch Test Series will be required. Following consultation a specialist nurse will apply the patch tests on your back. This first appointment will last up to 45 minutes.

The second appointment is on Thursday (of the same week): This appointment may again take up to 30 minutes and you will have the Patch Tests removed. The nurse will make an initial reading of the Patch Test and take photographs.

The final appointment is on the Friday: You will be seen again by the Dr Palamaras. He will make the final reading of the Patch Tests, then compare it with the one on Thursday and talk to you about what has been found. If you have been found to have any allergies, Dr Palamaras will give you written information about these at this appointment. He then may discharge you back to your GP’s or referring doctor’s or may make a further appointment for you for review.

What should I bring to the Patch Test Clinic?

Please bring the following to the first appointment:

  • A list of all your prescribed medications including any prescribed creams or ointments that you have used on your skin,

  • Any over-the-counter creams or ointments that you have used,

  • Any substances that you use at home, at work or at leisure that you feel might be causing a problem with your skin, for example toiletries, cosmetics, nail varnish. Please bring these in their original containers with the original packaging if possible so that Dr Palamaras can see the list of the ingredients. Dr Palamaras will then decide whether there is any indication to Patch Test you with any of the above.

Where are the Patch Tests applied?

They are usually placed across your back but some times your upper arms or thighs might need to be used.

How to look after your Patch Test

  • Do not get the Patch Test area wet during the test ( i.e. no baths or showers until after the final reading on the Friday although washing areas, other than the Patch Test site, with a flannel is acceptable).

  • Do not engage in any activities that may make you hot and sweaty as the patches may come off e.g. squash, tennis or football.

  • Do not go swimming until the end of the test.

  • Do not use any creams or ointments on your skin on the day of the test as this might make it difficult to apply the patches to your skin.

  • Wear old clothes: t-shirt, bra, especially on the first day of the test. The patches are held on with tape and are marked with a surgical skin marker pen. The pen might mark your clothing and you might not be able to wash this out. You will be able to wash the pen marks off your skin at the end of the test.

  • If the patches start to peel off, re-enforce them with more tape.

  • If the patches fall off make a note of the date and time when this happened and contact Dr Palamaras.

  • If a patch causes intolerable itching or burning then take it off, make a note of the date and time and contact Dr Palamaras.

  • Do not expose your back to the sun or use a sunbed during the week of the test

What are the side-effects of the Patch Test Investigation?

Side effects are rarely encountered but can include any of the following:

  • Your skin may become red and itchy especially where there is a positive Patch Test result. This reaction usually settles after a few days without treatment. If you have a more severe reaction, the Dermatologist may prescribe you some creams to help alleviate the symptoms.

  • Some positive reactions can persist for longer periods of time – up to a month or more, although this is unusual. The Patch Tests might cause your existing skin problem to flare.

  • Some Patch Tests cause an increase of pigmentation in the skin at the site of the tests and this again may persist for some time.

  • If there is a very strong reaction to one of the Patch Tests, this can allow the skin to become infected and occasionally scarring has occurred in the Patch Test site. This happens very rarely.

  • There is a small risk that you might become allergic to one of the substances used during the Patch Test. This happens rarely, about 1 in 500 Patch Tests.

Can I take my usual medications whilst having the Patch Tests?

  • It is fine to take antihistamine tablets by mouth whilst having the Patch Tests.

  • If you are taking steroid tablets by mouth, you will need to discuss the dose with Dr Palamaras. Also, if you are taking any type of immunosuppressive medication (such as ciclosporine, methotrexate, azathioprine, mycophenolate mofetil etc), you will need to inform Dr Palamaras as these may alter the validity of the Patch Test.

Can anyone have a Patch Test?

Dr Palamaras will not carry out Patch Tests on pregnant patients, women who are breast feeding, patients who have had sun exposure or have used a sun bed in the previous two weeks and patients who are taking more than 10 mg of oral prednisolone daily.

If you have any other questions about the Patch Tests, please ask Dr Palamaras or one of the nurses before you leave the clinic. If you think of any questions that you would like answered after you leave the clinic, please contact Dr Palamaras.

Dr Ioulios Palamaras Ioulios Palamaras MD PhD

Dr Palamaras is a Consultant Dermatologist and Head of Department at the Royal Free, Barnet and Chase Farm NHS Trust Hospitals. He was also Honorary Mohs and Laser Consultant Surgeon at St John's Institute of Dermatology, Guy’s and St Thomas’ NHS Foundation Trust.

Dr Palamaras is a member of the following societies: