Laser and Skin Clinics icon

Patch Testing

Patch testing is done to see whether a particular substance is causing an allergic skin reaction (contact allergic dermatitis); it tests for Type IV (delayed) allergy. Patch test can detect a delayed allergic reaction on the skin that can take a few days to develop.

contact us View Prices

Contact allergic dermatitis often manifests with persistent or fleeting, itchy skin rashes on the head and neck, hands, vulva or any other part of your skin.

Patch Tests: Requires 3 Visits for Application of Tests and Reading

Patch tests are only helpful to investigate allergies which are due to direct skin contact with substances outside the body. These include metals, perfumes, rubber, colophony in sticking plaster, and preservatives found in many cosmetics, shampoos, shaving foams and creams. These substances/allergens are applied to the patches, which are then placed on your skin.

Testing involves three visits to the clinic:

First Visit – Application of the Patches on the Back

On the first visit, the specialist nurse will apply the allergens under a special tape across the whole back. The allergens are applied in aluminium Finn chambers and left in place 48-hours. During this time you will be unable to wash or shower or exercise to avoid sweating.

Second Visit – Reading and Skin Re-Marking

The patches are removed, and the skin marked at the site of the original application. We take a reading of the skin reaction at this visit to look for irritant and allergic reactions.

Third Visit- Final Reading

The skin specialist will assess the skin and determine whether there have been any positive reactions. Information sheets will be provided about any detected allergies.

GP referral letters are only required if you are planning to claim any consultation fees from your private medical insurance company. Private medical insurance companies will normally cover the costs of skin-prick and patch-testing. We accept self-referrals to the clinic.

Is patch testing safe?

Yes. Patch testing does not trigger severe/life-threatening allergic reactions.

Are there any risks or complications?

Most positive reactions (small itchy bumps on the back) will resolve within a day or two. Rarely one or more can persist longer and be itchy/uncomfortable. The doctor will prescribe you a steroid cream to calm down any strong reaction that lasts longer than a few days.

Rarely, a positive reaction to an allergen can trigger a generalised eruption of eczema. This may occur in patients who are extremely sensitive to a particular substance or who suffer from moderate to severe eczema.