A drug allergy occurs when the immune system overreacts to a substance within the drug itself. A drug allergy can come from any form of medication, whether it is in liquid, pill or injectable form.
All medications can trigger an allergic reaction, but the most common allergy inducing medications are:
- Antibiotics, such as penicillin
- Aspirin and non-steroidal anti-inflammatory medications, such as ibuprofen
- Monoclonal antibody therapy
The chances of developing an allergy are higher when you take the medication frequently or when it is rubbed on the skin or given by injection, rather than taken by mouth.
You may not develop an allergic reaction to a drug the first time it is administered but develop an allergic reaction the next time you take the drug. In this case, your body has built antibodies against it and will develop symptoms as the body tries to defend against the drug re-entering your system.
The most common symptoms associated with a drug allergy are:
- Skin rash or hives
- Wheezing or other breathing problems
- Feeling dizzy or light-headed
Drug allergies can be hard to diagnose, but you can meet with an allergist who will dive into your health history looking for any consistent triggers to determine if your symptoms are allergic or non-allergic. Your allergist may also recommend a skin test or blood test to determine if the drug of concern is affecting your system. In some cases, an allergist will recommend an oral drug challenge to determine the allergy, which is done under the direct supervision of an allergist in a doctor’s office.
Management and Treatment
To manage a drug allergy:
- Make sure all of your doctors are aware of your allergy and the symptoms you experienced.
- Ask about related drugs that you should avoid.
- Ask about alternatives to the drug that caused your allergic reaction.
- Wear an emergency medical alert bracelet or necklace that identifies your allergy.
If there is not a suitable alternative to the drug you are allergic to, you may need to undergo drug desensitization.
If your drug allergy is life threatening, injectable epinephrine is usually prescribed as emergency medication for treating a life-threatening allergy.