02 May 2019
Allergists have long known that penicillin “allergy” is often over-diagnosed.
As outlined in a recent study referenced by The New York Times, at least 95% of patients can tolerate penicillins despite a previous history of allergy. This is quite important clinically since penicillin products are often safer and more effective than other more expensive antibiotics.
The allergists at the Westchester Health Asthma/Allergy division have expertise in dealing with drug allergies and regularly test and challenge with penicillins to ensure our patients can safely take these agents.
Because this is such an important issue, I’d like to summarize many of the points raised by The New York Times article so that parents can make informed decisions and possibly consider getting their child tested.
Millions of Americans who believe they are allergic to penicillin are not actually allergic.
Because of this, they are discouraged from taking some of the safest, most effective antibiotics, relying instead on substitutes that are often more expensive, less effective and more likely to cause complications such as antibiotic-resistant infections.
These are the conclusions of a new paper on penicillin allergy, published in January, 2019 in JAMA (Journal of the American Medical Association). The study was carried out with input from the boards of three professional medical organizations: the American Academy of Allergy, Asthma and Immunology; the Infectious Diseases Society of America; and the Society for Healthcare Epidemiology of America. All three groups endorsed the findings.
“Experts in allergy and infectious disease, including the paper’s authors, are now urging patients to ask doctors to review their medical history, and re-evaluate whether they have a true penicillin allergy,” the NYT article states.
Allergy experts urge patients to get tested to determine if they really are allergic. This may require allergy skin testing and should be done while the patient is healthy.
Though an allergy can develop at any age, penicillin allergies are often first detected in childhood.
If a child taking penicillin develops a rash or other symptoms and these are erroneously attributed to the antibiotic, the false allergy determination sticks, often for life. This is because when information alerting physicians about an allergy shows up on a patient’s chart, they typically don’t question it, assuming the patient can’t tolerate penicillin.
Some people do have potentially life-threatening allergic reactions to penicillin, but the label seems to have been applied far too broadly.
Approximately 10% of Americans report having a penicillin allergy, and the rate is even higher among older people and hospital patients. However, studies that have conducted allergy skin testing on patients whose medical records list a penicillin allergy have found that the overwhelming majority test negative. Case in point: A 2017 review of 24 studies of hospitalized patients found that overall, 95% tested negative for penicillin-specific antibodies, a sign of true allergy.
“We used to say nine out of 10 people who report a penicillin allergy are skin-test negative. Now it looks more like 19 out of 20,” said Dr. David Lang, president-elect of the American Academy of Allergy, Asthma and Immunology and chairman of allergy and immunology in the respiratory institute at the Cleveland Clinic.
Patients can get mislabeled as allergic to penicillin in a number of ways.
- They may experience bad drug reactions, such as headaches, nausea or diarrhea, which are not true allergic reactions but are misinterpreted.
- They may develop a symptom like a rash, which is indicative of a true allergic reaction but could be caused by an underlying illness and not by the drug.
- Many years after a severe allergic reaction, they may not experience that reaction again. In fact, once you can tolerate penicillin again, you have the same risk as someone who never had an allergy to it, said Dr. Kimberly Blumenthal, the review’s senior author, who is an allergist and an assistant professor at Harvard Medical School.
Patients should find out if they really are allergic because penicillin antibiotics (beta-lactams) are among the safest and most effective treatments for many infections.
Consider this evidence:
- Beta-lactams are the treatment of choice for Group A Streptococcus, which can cause pneumonia, toxic shock and other syndromes; Group B Strep, which causes meningitis; Staphylococcus aureus; and other pathogens.
- Beta-lactams are used prophylactically to prevent infections during surgery. Studies have found that patients with penicillin allergies who are given alternatives before surgery had a substantially greater risk of a surgical site infection.
- Beta-lactams are also the first line treatment for syphilis and gonorrhea.
- Penicillin substitutes like fluoroquinolones, clindamycin, vancomycin and third-generation cephalosporins are often less effective and more expensive. In addition, many of these are broader spectrum antibiotics, which can lead to the development of resistant organisms and other side effects.
- Studies have shown that patients with penicillin allergies are at increased risk for developing serious infections like Clostridium difficile, methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococcus, so if you are in fact not allergic, it’s important to know that.
Want to test if you’re allergic to penicillin? Talk to your doctor.
First, your doctor will take a careful history of your past reaction to penicillin and review the symptoms.
If these included headache, nausea, vomiting and itching, or the diagnosis was made based merely on a family history of the allergy, you are considered low risk. This means that you may be able to take a dose of penicillin or a related antibiotic, such as amoxicillin, under medical observation.
If your past reaction included hives, a rash, swelling or shortness of breath, you should undergo penicillin skin testing, which involves a skin prick test using a small amount of penicillin reagent, followed by a second test that places the reagent under the skin if the first test is negative. If both tests are negative, you are unlikely to be allergic to penicillin, and an oral dose may be given under observation to confirm.
If you want to know for sure if you have a penicillin allergy
Consider getting tested but only under the supervision of a physician.
Additional articles on this subject you might want to read:
- Patients Who Say They’re Allergic to Penicillin Are Usually Wrong
- PENICILLIN ALLERGY – WHAT DO YOU NEED TO KNOW?
- Do you really have a penicillin allergy?
- Am I Allergic to Penicillin?
- Think You’re Allergic to Penicillin? Check Again
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Got questions about penicillin allergy? We can help.
If you’re concerned or have questions about whether your child is allergic to penicillin, bring in your child to see one of our Westchester Health Pediatrics pediatricians. We’ll evaluate your child’s history and past symptoms and probably perform some tests to determine if there is in fact an allergy. Then we’ll go from there. As always, our #1 goal is to help you raise a happy, healthy child and for you to feel confident as a parent. Whenever, wherever you need us, we’re here for you.