If you think you have an allergy, tell your GP about the symptoms you're having, when they happen, how often they occur and if anything seems to trigger them.
Your GP can offer advice and treatment for mild allergies with a clear cause.
If your allergy is more severe or it's not obvious what you're allergic to, you may be referredfor allergy testing at a specialist allergy clinic.
Find your nearest NHS allergy clinic .
The tests that may be carried out are described below.
Skin prick testing is one of the most common allergy tests.
It involves putting a drop of liquid onto your forearm that contains a substance you may be allergic to. The skin under the drop is then gently pricked with a needle. If you are allergic to the substance, an itchy, red bump will appear within 15 minutes.
Skin prick testing is painless and very safe. Make sure you don't take Antihistamines before the test, as they can interfere with the results.
Blood tests may be used instead of, or alongside, skin prick tests to help diagnose common allergies.
A sample of your blood is removed and analysed for specific antibodies produced by your immune system in response to an allergen.
Patchtestsare used to investigate a type of eczema known as contact dermatitis , which can be caused by your skin being exposed to an allergen.
A small amount of the suspected allergen is added to special metal discs, which are then taped to your skin for 48 hours and monitored for a reaction.
If you have a suspected food allergy , you may be advised to avoid eating a particular food to see if your symptoms improve.
After a few weeks, you may then be asked to eat the food again to check if you have another reaction.
Don't attempt to do thisyourself without discussing it with a qualified healthcare professional.
In a few cases, a test called afood challenge may also be usedto diagnose a food allergy.
During the test, you're given the food you think you're allergic to in gradually increasing amounts, to see how you react under close supervision.
This test is riskier than other forms of testing, as it could cause a severe reaction, but is the most accurate way to diagnose food allergies. And challenge testing is always carried out in a clinic where a severe reaction can be treated if it does develop.
Read all about allergies, including about the most common allergies, what the symptoms of an allergic reaction are, and what can be done to keep an allergy under control.
Read about the main symptoms of an allergic reaction, including sneezing, wheezing, itchy eyes and shortness of breath.
Read about the tests that may be carried out to diagnose an allergy, including skin prick testing and blood tests.