While millions or people have a documented penicillin
allergy in their medical record, studies have shown that more 95% actually can
be treated safely with this class of antibiotics, improving treatment outcomes
and reducing the risk of infection with dangerous resistant pathogens such as C.
difficile. A review article in the January 15 issue of JAMA recommends
best practices for evaluation of reported penicillin allergies and provides
clinicians with guidance and tools to help determine appropriate procedures
based on the severity of previously reported reactions. 

Lead and corresponding author Erica Shenoy, MD, PhD,  Massachusetts
General Hospital (MGH) Division of Infectious Diseases, and senior author
Kimberly Blumenthal, MD, MSc, MGH Division of Rheumatology, Allergy and
Immunology, have been addressing the issue of penicillin allergy evaluation for
several years; and the current report is a result of a consensus development
among the American Academy of Allergy, Asthma and Immunology; the Infectious
Diseases Society of America, and the Society for Healthcare Epidemiology of

Shenoy explains that the common use of penicillin and related antibiotics is
behind the frequent documentation of penicillin allergy. “Many reported
penicillin allergies are established during childhood, when it is by far the
most commonly prescribed antibiotic. If a penicillin is prescribed for what is
actually a viral rather than a bacterial infection, a rash that develops may be
caused by the virus but attributed to a penicillin allergy, which then is
documented in the patient’s chart and never questioned again. The allergy label
can lead to patients’ not receiving penicillins and related drugs that are
often the best drugs to either treat or prevent common infections. When
alternatives are used instead, these can lead to increased risk of treatment or
prevention failure, as well as increased risk of C. difficile.” 

Key to the recommendations of the team is taking a comprehensive history of the
reaction that led to allergy documentation, which can help determine the
patient’s risk level and appropriate procedures for testing. Blumenthal says,
“A simple history can often distinguish intolerances – for example, headaches
or nausea – from allergies. Side effects should be judged by their severity
and, after discussion with the patient, clinicians should consider the safety
of a potential drug challenge. For patients whose symptoms – such as hives,
shortness of breath, wheezing or anaphylaxis – suggest a true allergic
reaction, this report provides guidance for evaluation, risk determination and
allergy management.” 

The authors stress that some form of evaluation of a documented penicillin
allergy can and should be carried out in any clinical setting – from routine
outpatient care to preparation for surgery or other procedures – and for all
patients with such documentation, including children and pregnant women. Shenoy
says, “I can’t think of a clinical encounter in which a careful allergy history
and then a planned course of action that may include penicillin skin testing,
amoxicillin challenge or referral to an allergist would not be of benefit to
the patient. If I had my way, verification of a penicillin allergy would be on
many of our checklists, just like age-related screenings and immunisations.
Evaluating a reported penicillin allergy, regardless of the current need for an
antibiotic, can lead to really important benefits for our patients.” 

Blumenthal adds, “It is my hope that all patients who believe they have a
penicillin allergy – including the parents of children with a documented
penicillin allergy – become aware that the allergy label may not be accurate,
is not benign and can be evaluated further. If such allergies are routinely
evaluated, patients will not needlessly avoid the beta-lactams that may be the
best treatment for their infection and reduce the development of antibiotic
resistance. Allergies to penicillin or to other drugs are very real, so it is
important not to be cavalier about the process of allergy evaluation. When
patients have an unclear or severe allergy history, allergists are available
and uniquely qualified to help with the assessment.” 

Source: https://www.massgeneral.org/about/pressrelease.aspx?id=2340

Reference: Shenoy
E, et al. Evaluation and Management of Penicillin Allergy: A Review. JAMA. 2019;321(2):188-199.
Published 15 January 2019.