Penicillin Skin Testing, Challenge, and Desensitization in Pregnancy: A Systematic Review

Antepartum versus postpartum amoxicillin oral challenge in pregnant patients with a reported penicillin allergy: A two-center prospective cohort study

INTRODUCTION

While 10% of pregnant individuals report a penicillin allergy, there is no established best practice for penicillin allergy delabeling in pregnancy. To better understand options for penicillin delabeling, we aimed to evaluate two penicillin allergy delabeling protocols in pregnancy regarding efficacy, adverse events, and patient satisfaction.

MATERIAL AND METHODS

From July 2019 to December 2022, we completed a two-center prospective cohort study, where each site recruited pregnant patients over 24 weeks gestational age with a reported penicillin allergy. One center offered antepartum amoxicillin oral challenges, either directly or after negative skin testing (i.e., antepartum oral challenge site). Our other centers completed a two-step approach with antepartum penicillin skin testing only and deferred oral challenges to the postpartum period (i.e., postpartum oral challenge site). Our primary outcome was the rate of penicillin allergy delabeling, defined as tolerating an antibiotic challenge with penicillin or amoxicillin. Univariate analyses were completed using chi-squared, Fisher's exact, and Wilcoxon rank tests.

RESULTS

During the study period, 276 pregnant patients were assessed, with 207 in the antepartum oral challenge site and 69 in the postpartum oral challenge site. Among the 204 patients who completed antepartum oral challenges, 201 (98%) passed without reactions. Deferring oral challenges to the postpartum period led to a loss of follow-up for 37/53 (70%) of eligible individuals. Overall, 97% (201/207) of patients at the antepartum oral challenge site were delabeled from their penicillin allergy-compared to 38% (26/69) of patients referred to the postpartum oral challenge site (p < 0.0001). Three antepartum oral challenge reactions were noted, including two mild cutaneous reactions and a case of transient abdominal discomfort.

CONCLUSIONS

Antepartum amoxicillin oral challenge is a more effective method to delabel pregnant patients from their penicillin allergy. Deferral of oral challenges to the postpartum period introduces a significant barrier for penicillin allergy delabeling.

Management of the Pregnant Patient with Beta-Lactam Allergy

PURPOSE OF REVIEW

We review the literature and discuss the logistics of testing pregnant patients for penicillin allergy.

RECENT FINDINGS

As in the general population, pregnant patients commonly report a penicillin allergy, but most patients are able to tolerate penicillin. Avoidance of beta-lactams in pregnancy is associated with increased morbidity: longer hospitalizations, more frequent infections, and more complications. Penicillin allergy testing is safe in pregnant patients, and obstetricians are eager for allergists to offer this procedure to their patients. As allergists, we can improve our patients' health outcomes by offering penicillin allergy testing in our practices. The protocols for testing both with and without skin testing in pregnant patients have been studied, and future studies will continue to clarify the safety and efficacy of penicillin allergy delabeling in pregnant patients.

Preoperative allergy testing for patients reporting penicillin and cephalosporin allergies is economically justified in preventing infection after total shoulder arthroplasty

BACKGROUND

The use of alternative antibiotics to cefazolin has been associated with increased risk of infection after shoulder arthroplasty. Routine preoperative allergy testing in patients reporting penicillin and cephalosporin allergies increases the number able to receive cefazolin and may reduce the occurrence of infection after shoulder arthroplasty, but the financial viability of this practice is unclear. We used break-even modeling to determine the economic viability of routine preoperative allergy testing for infection prevention in total shoulder arthroplasty patients reporting penicillin and cephalosporin allergies.

METHODS

Allergy testing cost ($248.24), infection rates after shoulder arthroplasty following use of noncefazolin antibiotics (3.09%), and infection-related care costs ($55,243) were derived from the literature. A break-even equation using these variables was developed to determine the absolute risk reduction (ARR) in the infection rate that would economically justify the routine implementation of preoperative allergy testing. The number needed to treat was calculated from the ARR.

RESULTS

Preoperative allergy testing is considered economically justified if it prevents at least 1 infection out of 223 shoulder arthroplasties (ARR = 0.45%). These protocols remained economically viable at varying allergy testing costs, initial infection rates, and infection-related care costs.

CONCLUSIONS

Routine preoperative penicillin allergy testing is an economically justified infection prevention strategy among patients reporting penicillin and cephalosporin allergies in the setting of elective shoulder arthroplasty. Widespread implementation of this practice may considerably reduce the economic and societal burden associated with prosthetic infections.

Review of Pharmacist Driven Penicillin Allergy Assessments and Skin Testing: A Multi-Center Case-Series

Objective: To describe the impact of pharmacy driven penicillin allergy assessments on de-labeling penicillin allergies and antibiotic streamlining opportunities for hospitalized patients. Design: Multi-center, retrospective case-series study. Setting: A health system of 4 non-teaching hospitals. Participants: Patients aged 18 years and older with a physician order for a pharmacist penicillin allergy assessment. Exclusion criteria consisted of patients with anaphylaxis or a type II penicillin allergy, anaphylaxis of any cause within 4 weeks, refusal of penicillin allergy skin test (PAST), antihistamine use within 24 hours, penicillin intolerance, immunosuppression or immunosuppressive medications, or skin conditions that could interfere with PAST. Interventions: The primary endpoint evaluated the number of de-labeled penicillin allergies after pharmacists provided penicillin allergy assessments. Secondary endpoints evaluated the percent of patients with antibiotics deescalated to beta-lactam antibiotics and classification of notable interventions made by pharmacists. Measurements and Main Results: There were 35 patients who met inclusion criteria. Twenty-four patients underwent both penicillin allergy skin testing and oral (PO) amoxicillin challenge. Five patients had allergies de-labeled only after a pharmacist interview. Four patients received only the PO amoxicillin challenge and 2 patients received only PAST. Penicillin allergies were de-labeled from the electronic health record (EHR) in 31 (89%) patients despite all testing negative for a penicillin allergy from PAST or a PO amoxicillin challenge. Four patients had the allergy re-added to the chart on subsequent admissions. No patients experienced a reaction from PAST, PO amoxicillin challenge, or subsequent beta-lactam antibiotics. Twenty-eight (80%) patients had their antibiotic therapy changed as a result of the allergy assessment. Seventeen patients were de-escalated onto beta-lactam antibiotics and aztreonam was stopped in 6 patients. Conclusion: Results from this study suggests that pharmacists expanding their scope of practice with PAST is a safe and effective allergy de-labeling tool. Pharmacist-driven penicillin allergy assessments could provide antibiotic cost savings and avoid aztreonam use. The study supports the need to emphasize education for patients and caretakers regarding allergy testing results to avoid relabeling in future hospital visits.

Improving routine prenatal penicillin allergy testing for reported penicillin allergy

BACKGROUND

Patients with self-reported antibiotic allergies have a higher cost of care, more frequent infections with resistant bacteria and worse health outcomes than patients without antibiotic allergies. Ultimately, less than 5% of patients who report a penicillin allergy have a clinically significant immune-mediated hypersensitivity reaction when tested. As 10%-30% of the population of pregnant patients are colonised for group B Streptococcus (GBS) and guidelines recommend penicillin as the treatment of choice for GBS, current recommendations support penicillin allergy testing in pregnant patients who report an allergy.

METHODS AND INTERVENTION

In this quality improvement project, nursing staff used an algorithm outlining inclusion and exclusion criteria to determine which patients were eligible to have penicillin allergy testing completed. Penicillin allergy testing consisted of a skin test using benzylpenicilloyl polylysine (Pre-Pen), penicillin G potassium, amoxicillin and alkaline hydrolysis mix (penicilloate) as a prick skin test, followed by intradermal skin test and finally an oral challenge with either amoxicillin or penicillin. Patient outcomes were analysed to evaluate the impact of the intervention.

RESULTS

Of the 1266 patients receiving prenatal care during the intervention, 236 (19%) reported a history of penicillin allergy, and 212 if these were eligible for testing. 150 of the eligible patients were offered penicillin allergy testing. 101 patients (67%) completed testing and 49 (33%) declined testing. Seven patients (7%) had positive penicillin allergy testing, while 94 patients (93%) had negative penicillin allergy testing and were immediately de-labelled as penicillin allergic. Seventeen of the de-labelled patients subsequently tested positive for GBS colonisation, and all received intrapartum penicillin without adverse events.

CONCLUSIONS

Pursuing penicillin allergy testing for pregnant patients with reported penicillin allergy is a safe and feasible approach, allowing for allergy de-labelling and safe, guideline-driven antimicrobial therapy during subsequent labour and delivery hospitalisations. Cost-effectiveness of the allergy testing and impact on later episodes of care should be further investigated.

Safety and outcomes of penicillin allergy evaluation in pregnant women

BACKGROUND

Penicillin allergy in pregnancy is associated with increased morbidity and the use of less effective antibiotics. Penicillin allergy evaluation in pregnancy is now recommended as per obstetrical guidelines but remains infrequent.

OBJECTIVE

We studied pregnant women who underwent penicillin allergy evaluation in an allergy clinic to assess the effectiveness and safety of penicillin skin testing (PST) and incremental drug challenge (IDC) in pregnancy.

METHODS

Index drug reactions, PST, and IDC results were reviewed. Antibiotic use, pregnancy outcomes, and pregnancy complications were compared with a control cohort of pregnant women with penicillin allergy who did not undergo allergy evaluation before delivery.

RESULTS

Penicillin allergy was evaluated in 136 women. Culprit drugs included penicillin (37%), amoxicillin (30%), and unknown (20%). Index reactions occurred greater than 5 years ago in 91%, and these reactions were cutaneous or unknown in 92%. Of the 133 patients who underwent skin testing, 131 (99%) had negative or equivocal results and proceeded to incremental challenge. All 131 women passed penicillin IDC. Of the 69 women who ultimately used intrapartum beta-lactam antibiotics, all but 1 patient tolerated them. Women who underwent penicillin allergy evaluation did not have an increased risk of cesarean delivery or other pregnancy complications when compared with women without penicillin allergy evaluation.

CONCLUSION

PST and IDC can be safely conducted in pregnant women. When evaluated as low risk, most women tolerate IDC and can receive penicillin intrapartum without adverse reactions or negative pregnancy outcomes.

Algorithm to guide re-exposure to penicillin in allergic pregnant women with syphilis: Efficacy and safety

Background

Gestational syphilis is underdiagnosed and undertreated, leading to stillbirth, prematurity, low birthweight, neonatal death, and congenital syphilis. Most patients who label as allergic to penicillin are misdiagnosed.

Objective

To assess the efficacy and safety of an algorithm to guide re-exposure to penicillin in pregnant women with syphilis and reporting allergy to the antibiotic.

Methods

We performed a prospective study assessing pregnant women with syphilis and labeled as allergic to penicillin. Based on clinical history, patients were divided in two groups: high-risk and low-risk to penicillin allergy. Low-risk patients with negative skin testing and negative serum specific IgE to penicillin underwent drug provocation test. The remaining patients underwent desensitization.

Results

Ninety-one patients were enrolled. Allergy to penicillin was confirmed in 7.69% of pregnant women with syphilis and clinical history of allergy to penicillin; in all cases the diagnosis was made through intradermal testing, which predicted 100% of the breakthrough reactions observed during rapid drug desensitization (p < 0.001). Risk stratification based on the initial clinical reaction and skin testing to guide penicillin re-introduction through drug challenge or desensitization was safe (97.8%) and effective (97.8%).

Conclusion

We developed and showed the efficacy and safety of an algorithm to guide re-exposure to penicillin in pregnant women with syphilis and labeled as allergic to this drug. Intradermal test is an excellent biomarker in the diagnosis of immediate hypersensitivity reaction to penicillin and to predict breakthrough reaction during rapid drug desensitization. Further studies may confirm the greater safety of the intravenous protocol compared to the oral protocol.

Outpatient Penicillin Allergy Testing in Pregnant Women Who Report an Allergy

Pregnant women are accepting of outpatient penicillin allergy testing, and most who report an allergy test negative.

OBJECTIVE:

To estimate the feasibility, acceptability, and safety of outpatient penicillin allergy testing among pregnant women.

METHODS:

We conducted a prospective cohort study at a large academic hospital from March 2019 to March 2020. We recruited pregnant women with a self-reported penicillin allergy who underwent allergy testing between 14 0/7 and 36 6/7 weeks of gestation.

RESULTS:

Of 127 eligible women pregnant women, 74 (58%, 95% CI 4–67%) accepted allergy testing. Fifty completed or intended to complete allergy testing, yielding a feasibility rate of 68% (95% CI 56–78%). Among the 46 women actually tested (who ranged in age from 18 to 42), 93% (95% CI 68–100%) had a negative test result. A systemic reaction (symptoms consistent with anaphylaxis) occurred in only 2 women (4%, 95% CI 0.5–15%) despite 20 (43%) reporting a severe allergy. No woman suffered an adverse event as a result of allergy testing. In multivariate analysis adjusting for age and parity, women with public insurance had decreased odds of undergoing penicillin allergy testing (adjusted odds ratio 0.24, 95% CI 0.08–0.69).

CONCLUSION:

Outpatient penicillin allergy testing is acceptable and feasible in pregnancy.

An old disease on the rise: new approaches to syphilis in pregnancy

PURPOSE OF REVIEW

Maternal and congenital syphilis infection is on the rise in the United States and worldwide. Without adequate testing or provider recognition of infection, treatment can be neglected resulting in significant perinatal morbidity and mortality. This review article discusses the epidemiology of T. pallidum, describes novel diagnostic tests, and considers the need to expand therapeutic options.

RECENT FINDINGS

A new chemiluminescence immunoassay for use in the reverse-sequence algorithm is more sensitive and specific in pregnant women than previously noted and is helpful for identifying pregnant women at highest risk for neonatal congenital syphilis. Point-of-care testing may be used to detect early syphilitic disease and provide same-day testing and treatment. Randomized control trials of oral cefixime for treatment of syphilis are paving the way for potential use in pregnant women. Penicillin skin testing, challenge, and desensitization in pregnancy can be done safely.

SUMMARY

Congenital syphilis is a preventable disease and treatable infection in the modern world, but we are still met with challenges in its eradication. We should proceed with advancing efficient laboratory testing, expanding medical therapy, and implementing public health measures to curb the rise of the disease.

Induction of penicillin tolerance during pregnancy: Allergological opinion on the recommendation of the current AWMF Guidelines on Diagnosis and Treatment of Syphilis (AWMF Registry No. 059-002)

Not available.

Skin testing and oral amoxicillin challenge in the outpatient allergy and clinical immunology clinic in pregnant women with penicillin allergy

BACKGROUND

Penicillin allergy is frequently reported. In pregnant women, reported penicillin allergy is associated with negative health outcomes and suboptimal group B streptococcal prophylaxis. For individuals having penicillin allergy, skin testing followed by an observed oral challenge is recommended. Previous data indicate a low risk of adverse reaction with skin testing in pregnant women, but the subsequent oral challenge was not routinely pursued.

OBJECTIVE

To determine whether skin testing followed by the outpatient oral challenge is tolerated by pregnant women.

METHODS

We conducted a retrospective review of all pregnant women who underwent penicillin allergy evaluation at an outpatient allergy and clinical immunology clinic. The patients underwent oral amoxicillin challenges based on the discretion of the allergy provider. We evaluated the index reaction history, skin test results, oral challenge results, and subsequent antibiotic exposure.

RESULTS

A total of 46 pregnant women underwent skin testing without adverse reactions, of whom 44 patients (95.6%) received negative results. A total of 18 women (39%) completed an oral challenge without adverse reactions. Patients challenged vs not challenged did not differ in patient age, gestational age, latency since index reaction, or reaction history risk level. Notably, 28 women received intrapartum antibiotics. There was no difference in intrapartum antibiotic administration between those who did or who did not complete an in-office oral challenge (P = .90).

CONCLUSION

Penicillin skin testing and oral challenge in pregnant women can safely be performed in the outpatient setting. There was no difference in the intrapartum antibiotic use between women who were and those who were not challenged. Further research is needed to determine the utility of oral challenge in pregnant patients.