Symptoms:

• Anaphylaxis, or severe allergic reaction (see below)
• Hives
• Itching of the skin or eyes (common)
• Skin rash (common)
• Swelling of the lips, tongue, or face
• Wheezing

Symptoms of anaphylaxis include:

• Abdominal pain or cramping
• Confusion
• Diarrhea
• Difficulty breathing with wheeze or hoarse voice
• Dizziness
• Fainting, lightheadedness
• Hives over different parts of the body
• Nausea, vomiting
• Rapid pulse
• Sensation of feeling the heart beat (palpitations)

Signs and tests:

An examination of the skin and face may show hives, rash, or angioedema (swelling of the lips, face, or tongue). Decreased blood pressure, wheezing, and other signs may indicate an anaphylactic reaction.

Skin testing may help diagnose allergy to penicillin-type medications. Unfortunately, there are no good skin or blood tests to help diagnose other drug allergies. If you have had allergy-like symptoms after taking a medicine or receiving contrast (dye) before getting an x-ray, your doctor will often tell you that this proof that you have a drug allergy. No further testing is required.