Patch test information

• Patch testing can help your doctor find out if your skin condition is due to an allergy caused by something that is regularly in contact with your skin.
• Skin contact with an allergen might occur at home, at work or during your free time.
• Patch Testing does not test for food allergies, animals, dust or pollens.
• Patch testing is not painful and does not involve any injections.

This test is done in our Dermatology Department, the address and directions are at the end of the page.

• You will be tested to around 40 standard substances commonly in contact with the skin, including nickel, preservatives, perfumes and rubber.
• Additional substances will be included depending on your skin problem.
• You may be tested to some of your own work or home products.

One week prior to patch testing please contact the department if:

• You are taking steroid tablets (over 10mg per day) Prednisolone.
• You have extensive eczema on your back.
• You are pregnant / breastfeeding.
• If you have had sun exposure including sunbeds or light therapy in the past two weeks.

Yes, you can continue to take anti-histamines, but please inform us at your first patch test clinic appointment.

• Your own products, substances that you have been advised by the doctor that you might be allergic to.
• Work chemicals, if the doctor thinks that chemicals at work may be causing the problem, please deliver samples in well-sealed and labelled containers 2 weeks before your appointment to the dermatology unit.

Please bring the Health and Safety Data sheets, which will be available in your place of work. The doctor will advise you if this is required.

You will need to attend the hospital on 3 separate days in the week.

On the first visit:

you will be assessed by the nurse.

• The substances to be tested will be applied in special small containers to your back attached by hypoallergenic tape.
• Please do not apply a moisturiser to your back on the morning of this appointment.
• The sites are marked with a skin marker pen. If you have a very hairy back it would be helpful if you could shave the area before attending your appointment.

On the second visit, 48 hours later, most of the patch tape is removed and any reactions noted. Only the top of the tape and marker pen will remain.

On the third visit, 96 hours later, your back will be examined and any reactions discussed with you by the doctor.

• The sites may itch. This is normal.
• Positive reactions become red and itchy at the test site and usually become apparent by the third reading.

This is helpful since, as far as we can, we have eliminated contact allergy as a cause of your skin problem.