Posted on July 30, 2007 in Latest News
A drug allergy is an adverse reaction of the body’s immune system to a specific drug. Most people confuse it with Drug Reaction. However Drug reactions occurs becasue of the reaction of two drugs inside a human body, and is related to the drug’s mode of action. But drug allergy is caused by the action of certain drugs on body.
Less than ten percent of drug reactions are allergic in nature. If you suffer from a known drug allergy, always inform the health care provider before you undergo any medical treatment. To avoid complications wear a medical alert tag or carry the information about the drug allergy in your wallet.
Causes of drug allergy
Most common causes of drug allergy are aspirin, painkillers, NSAIDS, and antibiotics like penicillin, sulpha drugs and tetracycline. Some anti seizure medications can cause allergy in some people, while some individuals have a genetic allergy to some drugs. People at risk of a drug allergy are those who have previously taken large amounts of the drug, or taken injections of the drug.
Mechanism of a drug allergy
Sometimes a small dose of the allergen can trigger a reaction, while sometimes you may take the entire dose of the medicine and not have an allergy. In the latter case you may have a severe drug allergy the next time you take the medication. What happens is that consumption of the allergy-inducing drug sensitizes your body to produce immunoglubulins (Ig) E antibodies to counter and identify the drug. These antibodies produce histamines that create allergy.
Symptoms of a drug allergy
A drug allergy can be mild, moderate or severe. It may occur days or weeks after exposure to the drug and is fatal only in rare cases. A mild allergy causes rash, itching and localized hives. You may become sensitive to light and develop red, raised patches on the skin. A moderate allergy can cause swelling in the face, fall in blood pressure, breathlessness and erratic heartbeat. A severe allergy manifests itself in the form of anaphylaxis where the patient starts choking and the blood pressure falls rapidly. Anaphylaxis occurs within an hour of taking the drug.
A mild adverse drug reaction on the other hand results in vomiting, diarrhea, headache, insomnia or fatigue. A moderate drug reaction can cause excessive bleeding, puzzlement, and damage to the vital organs like kidney and liver and muscle wastage. Some people may be allergic to aspirin and NSAIDS and this causes an asthma attack, similar to an Ig E induced allergic reaction.
Treatment of a drug allergy
You can detect an allergy to penicillin by undergoing a skin test, while detecting other drug allergies may require a blood test. For a mild allergy stop taking the drug immediately and take anti-histamine to stop the itching and rash. Moderate allergy requires administration of corticosteroids, while the person needs an epinephrine injection in case of an anaphylaxis. In case of a severe allergy you must immediately rush to the emergency department of a hospital.
The most important step is to identify the drug causing the allergy and to avoid taking it in future.
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