Drug Allergies
What Is a Drug Allergy?
Many people may use the term “medicine allergy” or “drug allergy.” Most reactions caused by medications are more correctly termed “adverse reactions to drugs.” True drug allergies are rare. People with a drug allergy have an overly sensitive immune system that reacts to the drug as if it were an invader. The classical symptom of a drug allergy is hives, but symptoms may also include: Wheezing, shortness of breath, swollen throat and mouth, nausea, vomiting, diarrhea, and abdominal pain. Anaphylaxis is the most severe acute form of a drug reaction.
If you develop a rash, hives, or difficulty breathing after taking certain medications, you may have a drug allergy. As with other allergic reactions, symptoms can occur when your body’s immune system becomes sensitized to a substance in the medication, perceives it as a foreign invader, and releases chemicals to defend against it. People with drug allergies may experience symptoms regardless of whether their medicine comes in liquid, pill or injectable form. If you feel confused about your symptoms and which medications are safe for you to take, it’s time to take control and see an allergist at the Sinus Institute of Atlanta.
What are the Symptoms of a Drug Allergy?
While you may not experience allergic symptoms the first time you take a drug, your body could be producing antibodies to it. As a result, the next time you take the drug, your immune system may see it as an invader, and you’ll develop symptoms as your body releases chemicals to defend against it. Symptoms of a drug allergy may include:
- Hives
- Itching
- Wheezing or other breathing problems
- Swelling
- Anaphylaxis
Penicillin causes most allergic drug symptoms, but just because you show allergic symptoms after taking penicillin doesn’t mean that you will react to related drugs, such as amoxicillin, but it’s more likely. Also, just because you had a reaction to penicillin (or any other drug) at one time doesn’t mean you will have the same reaction in the future.
Antibiotics that contain sulfa drugs, such as Septra, Bactrim, and Pediazole occasionally cause allergic reactions. Nonantibiotic drugs containing sulfa are very low risk.
How are Drug Allergies Diagnosed?
Drug allergies can be hard to diagnose. An allergy to penicillin-type drugs is the only one that can be definitively diagnosed through a skin test. Some allergic reactions to drugs – particularly rashes, hives and asthma – can resemble certain diseases.
Dr. Sinha will want to know the answers to these questions:
- What drug do you suspect caused your reaction?
- When did you start taking it, and have you stopped taking it?
- How long after you took the drug did you notice symptoms, and what did you experience?
- How long did your symptoms last, and what did you do to relieve them?
- What other medications, both prescription and over the counter, do you take?
- Do you consume herbal medications or take vitamin or mineral supplements? If so, which ones?
Dr. Sinha will also want to know whether you have had a reaction to any other drug. If you can, bring the suspected drug with you. This will help Dr. Sinha recommend alternatives as needed.
Depending on the drug suspected of causing the reaction, Dr. Sinha may suggest a skin test or, in limited instances, a blood test. A blood test may be helpful in diagnosing a severe delayed reaction, particularly if your physician is concerned that multiple organ systems may be involved.
If a drug allergy is suspected, Dr. Sinha may also recommend an oral drug challenge, in which you will be supervised by medical staff as you take the drug suspected of triggering a reaction.
Penicillin Allergy
Nearly everyone knows someone who says they are allergic to penicillin. Up to 10% of people report being allergic to this widely used class of antibiotic, making it the most reported drug allergy. However, studies have shown that more than 90% of those who think they are allergic to penicillin, are not. In other words, 9 out of 10 people who think they have penicillin allergy are avoiding it for no reason. Even in people with documented allergy to penicillin, only about 20% are still allergic ten years after their initial allergic reaction.
Anyone who has been told they are penicillin allergic, but who hasn’t been tested by an allergist, should be tested. At the Sinus Institute of Atlanta, an allergist will work with you to find out if you’re truly allergic to penicillin, and to determine what your options are for treatment if you are. If you’re not, you’ll be able to use medications that are safer, often more effective and less expensive..
Penicillin Allergy Treatment
Those who have severe reactions to penicillin should seek emergency care, which may include an epinephrine injection and treatment to maintain blood pressure and normal breathing.
Individuals who have milder reactions and suspect that an allergy to penicillin is the cause may be treated with antihistamines or, in some cases, oral or injected corticosteroids, depending on the reaction. If you suspect you have a drug allergy, schedule an appointment with the Sinus Institute of Atlanta for testing and to determine the right course of treatment for you.