Aspirin sensitivity is common, especially in people with asthma or sinus problems. But a true aspirin allergy — in which your immune system overreacts to the drug — is rare. Signs and symptoms of aspirin allergy or sensitivity range from mild to serious and may include:

Hives
Itchy skin
Itchy, watery eyes
Swelling of the lips, tongue or face
Breathing difficulty or wheezing
These signs and symptoms usually occur within a few hours of taking the medication.

If you've had a reaction to aspirin, you should avoid all forms of aspirin, as well as other nonsteroidal anti-inflammatory drugs, such as ibuprofen and naproxen, which are chemically similar to aspirin. These drugs are found in many over-the-counter (nonprescription) medications. So check the label carefully.

If you think you might have an aspirin allergy, consult your doctor or allergist for advice. In rare cases, life-threatening reactions such as anaphylaxis can occur.