Skin allergy testing works by putting an allergen, such as milk or latex onto the skin to see how your skin reacts. A blood test is another way to diagnose if you have an allergy.
At The London Clinic we offer several types of allergy tests, which your allergy specialist will discuss with you.
Pin prick testing allows us to test for several possible allergens at the same time.
At The London Clinic the pin prick allergy test takes around 25 minutes.
First, we clean and sterilise the skin on your forearm.
Then we draw a numbered grid, from 1 to 16 on your forearm, using ink that you can wash off with water.
Finally we place a drop of liquid containing the allergen (e.g, pollen, dust mite, cow’s milk) on your forearm in one of the numbered boxes.
Your specialist then uses a sterile needle to gently prick your skin under the drop of liquid, containing the allergen. After fifteen minutes if any of the sections of skin on your forearm become bumpy, red and itchy, it indicates that you have had an allergic reaction to that substance.
When you come into contact with a substance that you are allergic to, your immune system releases a substance called histamine. Histamine causes the main symptoms of an allergic reaction, including red, itchy and bumpy skin, asthma-like breathing problems and rarely anaphylactic shock.
Patch testing helps your specialist identify which chemical (non-food) substances might aggravate your skin.
Patch testing does not detect allergies that might be related to diet, asthma or hay fever.
Patch testing at The London Clinic usually involves a few separate visits.
1. At your first appointment your consultant takes a complete medical history, to work out which substances you might be allergic to.
2. On your second visit your specialist will put some, pre-prepared patches on your skin, usually your back or upper arm. The patches are a way to test which environmental substances (allergens) you might be allergic to, such as latex, cosmetics and perfumes.
3. Each patch is pre-prepared by us and usually contains ten separate chemical substances (allergens). We will ask you to come back to the clinic after a couple of days so your specialist can check the patches. If any areas of the skin tested become red, bumpy or inflamed it indicates that the substance tested is an allergen. An allergy blood test is used in cases where pin prick or patch tests may not be suitable.
If you are pregnant, extremely sensitive, or have severe contact dermatitis, your specialist may take an allergy blood sample, to identify specific substances that you are allergic to.