Patch Testing

Positive patch testing

Patch testing is a process used to detect whether someone has allergic contact dermatitis. During patch testing, small amounts of chemicals or products that are used at work or home are diluted and placed onto discs mounted on hypoallergenic tape and then placed on the back.

The number of patches applied is specific to each individual. There are 10 discs on each patch, and up to 10 patches are placed on the back. 

Taking a history about your exposure to potential allergens at home and at work helps the doctor decide what the most likely problem substances are. It is not possible to test you against all available allergens, only the most likely.

Chemicals from the “Australian Baseline Series” are almost always used. There are 60 allergens in this series. If you have specific exposures to other chemicals, allergens from other series may be chosen. These are ordered from the Contact Allergen Bank Australia, in Melbourne.

Patches are applied on a Monday or Tuesday, and then removed on 2 days later. Dr Drummond or a practice nurse will check for any reactions at that time. There is a final appointment at 4-7 days to look for any late reactions.

The area of skin where the patches are applied must be kept dry for the duration of the testing.


Most patients have to attend 3 appointments over a 4-7 day period.

Appointment 1: 

Patients will have a consultation with Dr Drummond who will decide what needs to be tested. The clinic nurse will then make the patches up and stick them on to the patient’s back. This appointment may take up to an hour.

Appointment 2:

The patches are removed and the patient will then wait at least 15 minutes before their back is looked at to see if there have been any allergic reactions. This appointment lasts about ½ hour.

Appointment 3: 

Dr Drummond will again look at the patient’s back to see if there has been any other reactions appearing where the patches were. Dr Drummond will then discuss the results, management of your condition and skincare. The duration of this appointment depends on the results and complexity of the problem and its management.

Drummond Dermatology

Unit 16, Francis Chambers
40-42 Corinna St, Phillip ACT 2606

P: +61 2 5114 2682
F: +61 2 5114 2684


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