Allergic To Penicillin for Several Years? Perhaps Not

Health Professional, Medical Reviewer

Penicillin allergy represents the most common drug allergy in the United States. Somewhere between one and 10 percent of people avoid penicillin because of a history of reacting to it. But did you know 80-90 percent of the time it may not be a true penicillin allergy? Yes, many people are labeled "penicillin allergic" but, in fact, are not allergic to this class of drug. Why is this?

Drug reactions are documented, in most cases, purely by the report of a patient having an adverse response to a medication. When someone experiences a rash, itching, upset stomach, diarrhea, abdominal pain, swelling, dizziness, lightheadedness, throat symptoms or shortness of breath while taking a medication, drug allergy is appropriately considered. Unfortunately, all it takes is the consideration for health providers to make the claim of drug allergy.

True drug allergies are mediated by an antibody that we all have, and is referred to as IgE. When our bodies generate IgE antibodies to penicillin, we may develop an allergic reaction to it. Other types of reactions may occur and mimic allergic reactions. Sometimes the infection itself may cause many of the symptoms discussed above. So how do you know if it's an allergic reaction or not?

There is no easy blood test to identify people who are allergic to antibiotics and most other medications. But penicillin skin testing has been around for several decades and is probably one of the most underused procedures of this era.

Why is Penicillin Skin Testing Important?

  1. As stated above, many people who have a history (especially distant history) of a reaction to a penicillin drug are in fact not allergic to it. A negative skin test and negative oral challenge to penicillin (often part of the protocol) identifies whether there is true penicillin allergy. If the test or oral challenge is positive, penicillin and related antibiotics are restricted.

  2. Since there is a high likelihood, based on referenced studies, the testing will be negative, many children and adults will be able to have an antibiotic better matched to their infection.

  3. Often when penicillin allergy limits your doctor's choices, stronger antibiotics (meaning drugs able to kill a broader group of bacteria) are the only alternative. Stronger antibiotics have greater risks of side effects that include difficile toxin related diarrheal syndromes. Penicillin skin testing may reduce the incidence of these complications.

  1. Health officials continue to report concerns about bacteria that are resistant to many antibiotics. This is fostered by the use of strong antibiotics in hospitals and clinics. The use of broad-spectrum antibiotics may be reduced by correctly identifying penicillin-allergic patients.

  2. Health care expenditures may be reduced by millions of dollars since alternatives to penicillin can be much more expensive (especially in the hospital setting).** One of the studies, referenced below reports increased days in the hospital for patients allergic to penicillin.

  3. Penicillin-allergic people often pay more for alternatives to penicillin when a second antibiotic course is needed because of the failure to respond to the first one. Having to prescribe a second course of antibiotic whether the same alternative drug or another one (often more costly) increases the burden of expense and signals more missed days of school or work.

  4. Some people have multiple drug allergies that further narrow the spectrum of medications available if they become ill. No other antibiotic class (other than penicillin) has a commercially available and FDA (Food and Drug Administration) approved testing protocol. This means testing to penicillin may be crucial to the well-being of patients in this setting.

Final Words

Penicillin continues to be one of the most desirable first-line drug classes for throat, sinus and ear infections. This partially explains why so many people end up becoming allergic to it. The more frequent a drug is used, the more opportunities for an adverse effect. But when penicillin is avoided because of assumed allergy, a potentially greater problem emerges.

Penicillin skin testing is safe and has greater than 90 percent accuracy. The oral drug challenge that often follows the skin test proves you are tolerant to penicillin.

Adults and children who have been restricted from penicillin for years have an excellent chance of having it again. This could be a win-win situation for the patient and healthcare system.