Drug allergy is an allergy to a drug.

• An alergic reaction won't occur on the 1st exposure to a substance
• The 1st exposure allows the body to create antibodies and memory lymphocyte cells for the antigen
• However, drugs often contain many different substances, including dyes, which could cause allergic reactions. This can cause an allergic reaction on the 1st administration of a drug

• Medical attention should be sought IMMEDIATELY if an allergic reaction is suspected

• Most patients who believe they are allergic to aspirin are actually suffering froma  drug intolerance, and NOT a drug allergy

• Drug intolerance, which is a milder, non-immune-mediated reaction, that doesn't depend on prior exposure