What is a drug allergy?
A drug allergy is a bad reaction to a drug that happens when the body’s immune system responds to a drug as if it were a dangerous invader and tries to fight it off. Normally the body’s immune system should not react to a drug as though it were an invader, but some drugs can cause that response in some people.
A drug allergy is NOT the same as a drug side effect. Side effects are unintended or unwanted effects that drugs can cause.
What are symptoms of a drug allergy?
There are different types of drug allergies with their own set of symptoms.
“Immediate” allergy – it starts quickly after a drug is taken (usually within an hour or so). This type of allergy is serious because it can get worse if the medicine is continued. It can turn into a life-threatening whole-body allergic reaction, called anaphylaxis. Symptoms include:
- Wheezing or trouble breathing
- Chest tightness or pain
- Passing out or feeling as if you will pass out
- Swelling of your face, lips, tongue, or throat
- Hives
- Severe stomach ache or vomiting
- High fever
- Painful skin or skin blisters
Another type of drug allergy, called a “delayed” allergy, which more common. This type is not very serious and usually causes a rash that begins after a few days of taking a drug.
** Call 911 or contact your physician if you have any of the above symptoms.
Can I be tested for a drug allergy?
If your doctor suspects you have an immediate drug allergy, he or she might send you for allergy skin tests.
If you have a reaction that consists only of a rash (the type that is not serious), your doctor might want to send you to do a “drug challenge test.” For this test, the allergist will have you take a small amount of the drug that caused the rash while he or she observes you.