During an intradermal test, an allergist will inject a small amount of the allergen just below the surface of the skin on either your arm or back. Intradermal testing is better for allergens that display weaker allergic reactions. In approximately 15 minutes, a red bump will appear in that spot if you are positive for having an allergy. Any red bumps that appear during the skin test will disappear after about 30 minutes.
American College of Allergy, Asthma, and Immunology (acaai.org)
The American Academy of Allergy, Asthma & Immunology | AAAAI