Strategies to identify and prevent penicillin allergy mislabeling and appropriately de-label patients
Taking a good drug allergy history is critical, followed by removing the “penicillin-allergic” label in certain low-risk patients and referring for testing those at high risk.
PRACTICE RECOMMENDATIONS
› Obtain an accurate drug allergy history from all patients who have a listed penicillin allergy. B
› De-label penicillin allergy in patients who report symptoms of an adverse reaction (diarrhea, headache, or nausea) but who (1) do not have other systemic symptoms; (2) do have a family history, but no personal history, of a reaction; or (3) have tolerated the same penicillin derivative since the initial reaction. B
› Refer patients whose reaction history includes hives, shortness of breath, or other allergic-type signs and symptoms for potential skin testing or oral challenge, or both. B
Strength of recommendation (SOR)
A Good-quality patient-oriented evidence
B Inconsistent or limited-quality patient-oriented evidence
C Consensus, usual practice, opinion, disease-oriented evidence, case series
Patients presenting with urticaria or maculopapular rash after taking penicillin are particularly challenging.30 A study of patients in a primary care pediatrics practice found that 7.4% of children receiving a prescription for a penicillin reported a rash.32 Here, timing of onset of symptoms provides some clarity about the likelihood of true allergy. Rashes that manifest during the first hours after exposure are more likely to be IgE mediated, particularly when accompanied by other systemic symptoms; they should be considered high risk. Delayed-onset rashes (> 72 hours after exposure) are usually non-IgE mediated and therefore are generally lower risk,8,30,33 except when associated with certain features, such as mucosal involvement and skin peeling.
Despite acknowledging viral exanthems in the differential, many physicians still label patients presenting with any rash as “allergic.”28 Take care to look for other potential causes of a rash; for example, patients taking amoxicillin who have concurrent Epstein-Barr virus infection frequently develop a maculopapular rash.34 Caubet and colleagues found that 56% of pediatric patients with a history of nonimmediate rash and a negative oral challenge to amoxicillin tested positive for viral infection.28
A family history of penicillin allergy alone should not preclude the use of penicillin.8,27,31 Similarly, if a patient has already received and tolerated a subsequent course of the same penicillin derivative after the initial reaction, the “penicillin allergy” label can be removed. If the reaction history is unknown, refer the patient to an allergist for further evaluation.
Accurate charting is key. With most hospital systems and physician practices now documenting in an electronic health record, there exists the ability to document, in great detail, patients’ reactions to medications. Previous studies have found, however, that such documentation is often done poorly, or not done at all. One such study found that (1) > 20% of patients with a “penicillin allergy” label did not have reaction details listed and (2) when reactions were listed, many were incorrectly labeled as “allergy,” not “intolerance.”35
Many electronic health record systems lump drug allergies, adverse effects, and food and environmental allergies into a single section, leading to a lack of distinction between adverse reactions and true allergy.31 Although many PCPs report that it is easy to change a patient’s allergy label in the record,29 more often, a nurse, resident, or consultant actually documents the reaction.35
Continue to: Documentation at the time of the reaction...
