Drug Allergies - Certain medicines can trigger allergic reactions in some people. When the drug first enters the body, the immune system mistakenly responds by creating specific disease-fighting antibodies (called immunoglobulin E or IgE antibodies) that recognize the drug as a foreign substance. When the drug is taken again, these antibodies spring into action, releasing large amounts of histamine in an attempt to expel the drug from the body.

What Are The Symptoms Of Drug Allergies?

Symptoms can range from mild to life-threatening. Even in people who aren't allergic, many drugs can cause irritation, such as an upset stomach. But during an allergic reaction, the release of histamine can cause symptoms like hives, skin rash, itchy skin or eyes, congestion, and swelling in the mouth and throat.

A more severe reaction may include difficulty breathing, blueness of the skin, dizziness, fainting, anxiety, confusion, rapid pulse, nausea, diarrhea, and abdominal problems.

Foods and Allergies

The most common drug associated with allergies is penicillin. Other antibiotics similar to penicillin can also trigger allergic reactions.

Other drugs commonly found to cause reactions include sulfa drugs, barbiturates, anticonvulsants, insulin, local anesthetics such as Lidocaine, and iodine (found in many X-ray contrast dyes).

Diagnosing Drug Allergies

A physician diagnoses a drug allergy by carefully reviewing your medical history and symptoms. If your doctor suspects that you are allergic to an antibiotic such as penicillin, he or she may do a skin test to confirm it.

However, skin testing does not work for all drugs, and in some cases it could be dangerous. If you have had a severe, life-threatening reaction to a particular drug, your doctor will simply rule out that drug as a treatment option for you. Conducting an allergy test to determine if the initial reaction was a "true" allergic response isn't worth the risk.

How Are Drug Allergies Treated?

The primary goal when treating drug allergies is symptom relief. Symptoms such as rash, hives and itching can often be controlled with antihistamines, and occasionally corticosteroids.

For coughing and lung congestion, drugs called bronchodilators may be prescribed to widen the airways. For more serious anaphylactic symptoms -- life-threatening reactions including difficulty breathing or loss of consciousness -- epinephrine (adrenaline) is either inhaled or injected.

Occasionally, desensitization is used for penicillin allergy. This technique decreases your body's sensitivity to particular allergy-causing agents. Tiny amounts of penicillin are injected periodically in increasingly larger amounts until your immune system learns to tolerate the drug.

If you are severely allergic to certain antibiotics, there are alternative antibiotics your doctor can prescribe.

Talking With Your Doctor

If you have a drug allergy, you should always inform your healthcare provider before undergoing any type of treatment, including dental care. It is also a good idea to wear a MedicAlert bracelet or pendant, or carry a card that identifies your drug allergy. In cases of emergency, it could save your life.