Overview of the PRN

The Infectious Diseases Practice and Research Network (ID PRN) is composed of students, residents, fellows, pharmacists, and other clinical and research specialists who practice in the exciting area of infectious diseases. Serving 1162 total members, which include 132 students, 57 residents, and 18 fellows, the ID PRN is one of the largest PRNs within ACCP. Members are actively engaged in advancing pharmacy practice throughout an incredible variety of practice settings and believe strongly in education, research, credentialing, and professional stewardship. In addition, members are active and dedicated leaders on committees and executive boards within ACCP and other organizations.

Members of the ID PRN are dynamic, collaborative, supportive, and innovative. With a diverse and passionate membership base, the ID PRN recognizes how essential it is to engage members and consistently work together to extend the frontiers of clinical pharmacy practice. Our mission in our work is to disseminate knowledge and promote career opportunities for infectious diseases specialists to optimize patient outcomes and demonstrate the value of pharmacists across the health care continuum.

We encourage you to follow our social media pages to stay up-to-date with the latest practice advances in antimicrobial, antifungal, and antiviral pharmacotherapy! We can be found at:

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Opportunities and Resources

Resident and Fellow Opportunities

• Opportunity to serve on the Executive Committee
• To promote research and professional development, the ID PRN sponsors two $1000 awards to residents or fellows to present research posters at the ACCP Annual Meeting. Award recipients must present their original research in person at the ACCP Annual Meeting.
• Participate in the resident and fellow learner-led journal club series, which is presented on a monthly basis to national ACCP members, allowing trainees to develop presentation skills as well as gain invaluable feedback and insights into these topics
• Participate in the annual ID PRN mentorship program to serve as a mentor to a student

Student Opportunities

• Participate in the annual ID PRN mentorship program to be matched with a pharmacist, resident, or fellow mentor to help guide them in their professional development

All Trainee Opportunities

• Opportunities to serve on any ID PRN committee, including the Awards, Publications, Programming, Nominations, Networking, Research, and Social Media committees

The email list associated with ID PRN membership is active daily, inciting compelling clinical discussions and bringing attention to critical issues in practice. Networking is promoted through email list involvement, social media outlets, Annual Meeting attendance, pharmacy conference social events, research collaborations, and more. We welcome all who are interested in infectious diseases, even if it is not their current or primary practice area. The ID PRN website has great tools and resources for resident and student members. It also contains the contact information for all Executive Committee members. Please do not hesitate to reach out to us at [email protected]!

When the Label Does Not Fit: De-labeling Penicillin Allergies

Author: Anna Nahirnyak, Pharm.D.

Penicillin is the most commonly documented drug allergy, with around 10% of patients reporting a history of reacting to a penicillin-class antibiotic. However, fewer than 1% of the general population are truly allergic, and most (around 80% of patients) will lose the allergy after 10 years (Joint Task Force on Practice Parameters 2010). This is significant because penicillin allergy mislabeling leads to unnecessary broad-spectrum antibiotic use, increasing the risk of Clostridioides difficile infections, antibiotic resistance, and prolonged hospital stays and higher health care costs (Castells 2019). A 2018 study found that patients labeled as penicillin-allergic had a 50% higher risk of surgical site infections because of the use of second-line perioperative antibiotics (Blumenthal 2018a). Another large cohort study found that a penicillin allergy label was associated with a 69% increased risk of methicillin-resistant Staphylococcus aureus and a 26% increased risk of C difficile infections (Blumenthal 2018b). A 1993 study showed that routine penicillin skin testing enabled the safe administration of penicillin in over 90% of individuals previously labeled as allergic (Gadde 1993). These findings underscore the importance of integrating proactive penicillin allergy de-labeling initiatives into antibiotic stewardship programs to improve patient care (Castells 2019).

Immune reactions to penicillin are mainly antibody mediated (immediate reaction) or T-cell mediated (delayed reaction). As a hapten, penicillin binds to serum proteins in the body, which can trigger allergic reactions. Immediate, IgE-mediated reactions (type I) cause mast cells to release histamine, leading to symptoms such as urticaria, angioedema, bronchospasm, or anaphylaxis. T cell–mediated reactions (type IV) occur hours to weeks after exposure and can cause severe conditions such as drug reaction with eosinophilia and systemic symptoms, Stevens-Johnson syndrome and toxic epidermal necrolysis, or acute generalized exanthematous pustulosis. Of note, many patients may report a penicillin allergy given a family history or previous adverse effects such as headache or isolated GI symptoms; however, these are inconsistent with a true penicillin allergy and should not be documented as such (Castells 2019).

Table 1 summarizes the recommendations on de-labeling penicillin allergies published in the 2022 drug allergy practice parameter update by the American Academy of Allergy, Asthma & Immunology (AAAAI) (Khan 2022). Some patients with a history of nonallergic reactions may be instantly de-labeled by clinicians, whereas others, if deemed at low risk, may bypass penicillin skin testing and proceed directly to a drug challenge. Patients at low risk can be identified using the penicillin allergy clinical decision rule (PEN-FAST) introduced in 2021: 2 points are assigned for an allergic reaction within the past 5 years or for the severe nature of the reaction (eg, anaphylaxis, angioedema, or a severe cutaneous skin reaction), and 1 point is assigned if treatment was required for the allergic reaction or if the treatment history is unknown (Trubiano 2020). Patients with a PEN-FAST score of 2 or less are considered at very low to low risk of a positive penicillin skin test, and they can safely be de-labeled with an oral amoxicillin challenge without preceding skin testing as shown in the 2023 Use of Penicillin Allergy Clinical Decision Rule to Enable Direct Oral Penicillin Challenge (PALACE) trial (Copaescu 2023). Because skin testing and allergy consultations are not universally available and can be costly for patients, pharmacists should feel empowered to de-label patients with a low-risk penicillin allergy. In a study investigating a pharmacist-led, multidisciplinary approach to penicillin allergy de-labeling, 40 of 45 patients at low risk (88.9%) were successfully de-labeled, and 24 (53.3%) were changed to a penicillin antibiotic (Hearsey 2023). The Infectious Diseases Society of America Implementing an Antibiotic Stewardship Program guidelines also emphasize the importance of a multidisciplinary approach and the role of pharmacists in allergy de-labeling (Barlam 2016).

Patients with a true penicillin allergy who require antibiotic therapy may still be able to safely receive an alternative β-lactam antibiotic. Although the β-lactam ring is a common structural feature among penicillins, cephalosporins, carbapenems, and monobactams, differences in their R1 side chain play a key role in determining the extent of cross-reactivity (Castells 2019). According to the most recent findings, the risk of cross-reactivity in patients with a confirmed IgE- or T cell–mediated penicillin allergy was 16.45% for aminocephalosporins with identical side chains, 5.60% for cephalosporins with intermediate similarity, and 2.11% for those with low similarity scores. The risk of cross-reactivity to any carbapenem was very low at 0.87% (Picard 2019). Aztreonam appears to have no immunologic or clinical cross-reactivity with penicillins and most cephalosporins. However, hypersensitivity reactions to aztreonam have been reported in patients allergic to ceftazidime, which shares an identical R1 side chain with aztreonam and cefiderocol. Because of the particularly low risk of cross-reactivity between structurally dissimilar β-lactams, the AAAAI drug allergy practice parameter update recommends that patients with a penicillin hypersensitivity can safely be administered a structurally dissimilar cephalosporin without additional precautions (Khan 2022). Cross-reactivity charts can be used by clinicians to choose a safe alternative cephalosporin in patients with a confirmed penicillin allergy (Table 2) (Picard 2019; Zagursky 2018). An important exception to these recommendations applies to patients who have experienced severe delayed immunologic reactions or organ-specific reactions to β-lactams. Carbapenems can be administered without additional precautions regardless of whether the reaction to a penicillin was anaphylactic. The 2022 AAAAI document includes helpful flowsheets outlining the approach to β-lactam administration or allergy testing in patients with a history of β-lactam allergies according to the type of allergic reaction and the structural similarity of the antibiotics involved (Khan 2022).

In summary, integrating penicillin allergy de-labeling protocols into antimicrobial stewardship is crucial for optimizing antibiotic selection and patient outcomes while minimizing the harms of alternative therapy such as resistance, C difficile infections, and increased costs (Castells 2019; Blumenthal 2018a; Barlam 2016). For patients with confirmed penicillin hypersensitivity without a severe delayed immunologic reaction or organ-specific reaction, use of structurally dissimilar β-lactams ensures effective treatment without compromising patient safety (Khan 2022).

References

Barlam TF, Cosgrove SE, Abbo LM, et al. Implementing an antibiotic stewardship program: guidelines by the Infectious Diseases Society of America and the Society for Healthcare Epidemiology of America. Clin Infect Dis. 2016;62(10):e51-e77. https://doi.org/10.1093/cid/ciw118

Blumenthal KG, Ryan EE, Li Y, Lee H, Kuhlen JL, Shenoy ES. The impact of a reported penicillin allergy on surgical site infection risk. Clin Infect Dis. 2018a;66(3):329-336. https://doi.org/10.1093/cid/cix794

Blumenthal KG, Lu N, Zhang Y, Li Y, Walensky RP, Choi HK. Risk of methicillin resistant Staphylococcus aureus and Clostridium difficile in patients with a documented penicillin allergy: population based matched cohort study. BMJ. 2018b;361:k2400. https://doi.org/10.1136/bmj.k2400

Castells M, Khan DA, Phillips EJ. Penicillin allergy. N Engl J Med. 2019;381(24):2338-2351. https://doi.org/10.1056/NEJMra1807761

Copaescu AM, Vogrin S, James F, et al. Efficacy of a clinical decision rule to enable direct oral challenge in patients with low-risk penicillin allergy: the PALACE randomized clinical trial. JAMA Intern Med. 2023;183(9):944-952. https://doi.org/10.1001/jamainternmed.2023.2986

Gadde J, Spence M, Wheeler B, Adkinson NF Jr. Clinical experience with penicillin skin testing in a large inner-city STD clinic. JAMA. 1993;270(20):2456-2463.

Hearsey D, Elkhalifa S, Sandoe J, et al. Removal of incorrect penicillin allergy labels in a UK hospital. Clin Microbiol Infect. 2023;29(10):1338.e1-1338.e4. https://doi.org/10.1016/j.cmi.2023.06.024

Joint Task Force on Practice Parameters; American Academy of Allergy, Asthma and Immunology; American College of Allergy, Asthma and Immunology; Joint Council of Allergy, Asthma and Immunology. Drug allergy: an updated practice parameter. Ann Allergy Asthma Immunol. 2010;105(4):259-273. https://doi.org/10.1016/j.anai.2010.08.002

Khan DA, Banerji A, Blumenthal KG, et al. Drug allergy: a 2022 practice parameter update. J Allergy Clin Immunol. 2022;150(6):1333-1393. https://doi.org/10.1016/j.jaci.2022.08.028

Picard M, Robitaille G, Karam F, et al. Cross-reactivity to cephalosporins and carbapenems in penicillin-allergic patients: two systematic reviews and meta-analyses. J Allergy Clin Immunol Pract. 2019;7(8):2722-2738.e5. https://doi.org/10.1016/j.jaip.2019.05.038

Trubiano JA, Vogrin S, Chua KYL, et al. Development and validation of a penicillin allergy clinical decision rule. JAMA Intern Med. 2020;180(5):745-752. https://doi.org/10.1001/jamainternmed.2020.0403

Zagursky RJ, Pichichero ME. Cross-reactivity in β-lactam allergy. J Allergy Clin Immunol Pract. 2018;6(1):72-81.e1. https://doi.org/10.1016/j.jaip.2017.08.027