Doctors often use a type of skin allergy test known as a prick or scratch test as their first method when they are looking for an allergy. During a scratch test an allergen is put into a liquid. This liquid is then placed onto a small section of your skin with a very tiny puncture. 

Once you have been pricked with the allergen liquid you will be closely monitored to see if your skin reacts to the testing site with redness, swelling, puffiness, or itchiness. If any of this occurs then it means that you are allergic to the substance.

If a scratch test does not determine what is triggering your allergies then an allergist may do an intradermal skin test. This type of testing is similar to the scratch test in that your skin will be pierced with a little bit of the allergen. 

With intradermal testing you will be injected with the allergen so that it penetrates the first few layers of your skin. Once you have been injected with the allergen you will then be monitored for symptoms that show a reaction.

A third type of skin testing for allergies is the allergy patch test.

To do a patch test a doctor will place an adhesive patch that has been loaded with the substances that you may be allergic to. 

The patch test is a longer process than intradermal and scratch testing. You keep the patches on your skin after you leave the doctor’s office. After 2 days the patches are reviewed to see if there is any skin reaction. This review process usually is repeated again after 3 days and then finally after 4 days.

Find out about another type of allergy testing.