f you need patch tests, Dr Jones will be happy to recommend one of her colleagues.
Patch testing is used to detect an allergy to a substance that has come into contact with your skin. It does not detect allergies related to diet and it is better to see an immunologist if you would like to be tested for food allergies.
For the first appointment, it is recommended to bring any substances which you suspect may make your rash worse - for example cosmetics, perfumes, treatment creams, footwear. Any liquids should be brought in a leak-proof container and labelled. Unknown substances cannot be tested.
Patch testing requires three appointments usually Monday, Wednesday and Friday. The patch tests are applied on a Monday, removed and read on Wednesday and a final reading is taken on Friday. Any reactions are discussed after the final reading.
For accurate results attendance to all three visits is required.
Each visit usually lasts about half an hour.
At the first visit the allergens are placed on your back in metal discs and secured with tape. The patches are left on for two days. On the second visit they are removed and your back marked with a waterproof pen. Further substances may be applied at this stage, if the doctor thinks it is appropriate.
Patch testing cannot be performed if your rash is very active, if you have a sun tan or if you are pregnant.
The back must be kept dry for the five days of testing, so you may find it more convenient to have these tests when the weather is cooler