Skin testing for immediate hypersensitivity to betalactams: comparison between two commercial kits

The challenge of de-labeling penicillin allergy

BACKGROUND

Even though 8%-25% of most populations studied globally are labeled as penicillin allergic, most diagnoses of penicillin allergy are made in childhood and relate to events that are either not allergic in nature, are low risk for immediate hypersensitivity, or are a potential true allergy that has waned over time. Penicillin allergy labels directly impact antimicrobial stewardship by leading to use of less effective and broader spectrum antimicrobials and are associated with antimicrobial resistance. They may also delay appropriate antimicrobial therapy and lead to increased risk of specific adverse healthcare outcomes. Operationalizing penicillin allergy de-labeling into a new arm of antimicrobial stewardship programs (ASPs) has become an increasing global focus.

METHODS

We performed an evidence-based narrative review of the literature of penicillin allergy label carriage, the adverse effects of penicillin allergy labels, and current approaches and barriers to penicillin allergy de-labeling. Over the period 1928-2018 in Pubmed and Medline, search terms used included "penicillin allergy" or "penicillin hypersensitivity" alone or in combination with "adverse events," "testing," "evaluation," "effects," "label," "de-labeling," "prick or epicutaneous," and "intradermal" skin testing, "oral challenge or provocation," "cross-reactivity," and "antimicrobial stewardship".

RESULTS

Penicillin allergy labels are highly prevalent, largely inaccurate and their carriage may lead to unnecessary treatment and inferior outcomes with alternative agents as well as adverse public health outcomes such as antibiotic resistance.

CONCLUSIONS

Operationalizing penicillin allergy de-labeling as an aspect of ASP has become an increasing global focus. There is a need for validated approaches that optimally combine the use of history and ingestion challenge with or without proceeding formal skin testing to tackle penicillin allergy efficiently within complex healthcare systems. At the same time, there is great promise for penicillin allergy evaluation and de-labeling as an individual and public health strategy to reduce adverse healthcare outcomes, improve antimicrobial stewardship, and decrease healthcare costs.

Management of allergy to penicillins and other beta-lactams

The Standards of Care Committee of the British Society for Allergy and Clinical Immunology (BSACI) and an expert panel have prepared this guidance for the management of immediate and non-immediate allergic reactions to penicillins and other beta-lactams. The guideline is intended for UK specialists in both adult and paediatric allergy and for other clinicians practising allergy in secondary and tertiary care. The recommendations are evidence based, but where evidence is lacking, the panel reached consensus. During the development of the guideline, all BSACI members were consulted using a Web-based process and all comments carefully considered. Included in the guideline are epidemiology of allergic reactions to beta-lactams, molecular structure, formulations available in the UK and a description of known beta-lactam antigenic determinants. Sections on the value and limitations of clinical history, skin testing and laboratory investigations for both penicillins and cephalosporins are included. Cross-reactivity between penicillins and cephalosporins is discussed in detail. Recommendations on oral provocation and desensitization procedures have been made. Guidance for beta-lactam allergy in children is given in a separate section. An algorithm to help the clinician in the diagnosis of patients with a history of penicillin allergy has also been included.

Biological and genetic determinants of atopy are predictors of immediate-type allergy to betalactams, in Spain

BACKGROUND

Betalactam (BL) immediate-type allergy is influenced by environmental and genetic determinants, as illustrated by differences in worldwide prevalence and ethnicity from a same area and by associations with genes related to atopy.

AIMS

To evaluate the association of atopy with BL allergy.

MATERIALS AND METHODS

We measured specific Immunoglobulin E (IgE) against prevalent allergens and genetic predictors of atopy, IL13, IL4, IL4RA, IL4, and TNFA, in 340 patients and 340 controls from South of Spain.

RESULTS

Total IgE and IgE against mites were at higher concentration in patients. Patients with high total IgE and IgE against prevalent allergens had a slower decrease in BL IgE than nonatopic patients. IL4RA I50V and Q551R were associated with IgE against prevalent allergens and total IgE, respectively, and were also predictors of BL allergy.

CONCLUSION

Interacting determinants of atopy, total IgE, IgE against prevalent allergens, and IL4RA polymorphisms, contribute to the high prevalence of BL allergy in South of Spain.

Determining the negative predictive value of provocation tests with beta-lactams

BACKGROUND

The beta-lactam allergic work-up is mostly standardized. However, the negative predictive value of drug provocation tests is not yet well established.

METHOD

A historical-prospective multicentre cohort study was conducted in four centres (one in France, one in Portugal, two in Italy) to assess the negative predictive value of provocation tests with beta-lactams in patients initially tested for a suspicion of drug allergy/hypersensitivity. Patients were contacted at least 6 months after the work-up, between 2003 and 2007. A new allergic work-up was proposed to reacting patients.

RESULTS

Among the 457 patients included, 365 (79.9%) were followed up (159 [79.1%] from France, 153 [82.7%] from Italy and 53 [74.6%] from Portugal). Only 118 (25.8%) were re-exposed to the negatively tested beta-lactam. Nine (7.6%) reported a non-immediate (occurring more than 1 h after drug administration) reaction: five urticaria, three exanthema and one undefined cutaneous reaction. None were severe. Only four accepted a re-challenge, negative in two cases and positive in the two others. The negative predictive value was 94.1% (89.8-98.3) (111 out of 118 patients).

CONCLUSION

Although the negative predictive value of drug provocation tests may not be 100%, none of the false negative patients experienced a life-threatening reaction. This should reassure doctors who might hesitate to prescribe beta-lactams, even in patients with negative allergic work-ups.

Experience with a new commercial skin testing kit to identify IgE-mediated penicillin allergy

Many patients who describe a history of allergy to penicillin do not prove to be allergic and can be treated safely with penicillin. After a period of 2 years where testing of penicillin allergy was not possible, a new commercial kit has recently become available. We report our initial experience with use of the kit with 29 patients and discuss one patient who experienced anaphylaxis during i.d. testing.

Preoperative evaluation of patients with history of allergy to penicillin: comparison of 2 models of practice

OBJECTIVE

To study whether allergy consultation and penicillin allergy skin testing affects the selection of antibacterial prophylaxis perioperatively in surgical patients with history of allergy to penicillin (HOAP).

PATIENTS AND METHODS

From January 1 through June 30, 2004, we compared 2 different models of practice at our institution. At the Preoperative Evaluation Clinic (POEC), all patients with HOAP are evaluated by an allergist and undergo skin testing for allergy to penicillin. At other (non-POEC) preoperative evaluation settings (OPES), patients with HOAP do not undergo allergy consultation and penicillin skin testing before surgery. Of the 4889 patients screened at the POEC during the study period, 412 consecutive patients with HOAP were included in the study. Of the 416 patients screened at OPES, 69 consecutive patients with HOAP were studied. Logistic regression was used to assess whether allergy consultation was associated with the choice of antibiotic for antibacterial prophylaxis perioperatively, after adjusting for age, sex, and type of surgery.

RESULTS

Perioperative cephalosporin use was greater among patients screened at POEC vs those screened at OPES (70% vs 39%, P<.001 unadjusted; P=.04 adjusted for age, sex, and type of surgery). Vancomycin use was lower for patients screened at POEC vs those screened at OPES (10% vs 28%, P<.001 unadjusted; P=.03 adjusted).

CONCLUSION

For patients with HOAP, evaluation at the POEC was associated with increased use of cephalosporin and decreased use of vancomycin.

Oral challenges are needed in the diagnosis of beta-lactam hypersensitivity

BACKGROUND

beta-lactams continue to remain the most commonly involved drug family in allergic drug reactions. They are often essential and there is a cost-effective and favourable risk-benefit ratio for the exploration of all suspicions of beta-lactam allergy. A firm diagnosis is always based on skin tests and sometimes on provocation tests. Recommendations have been published by allergy societies and distinguished scientists but they are not always concordant and can lead to some confusion for the practicing allergologist. The situation has even worsened since the world wide withdrawal of these penicillin determinants and since the predominance of amoxicillin and cephalosporin prescriptions in most countries. OBJECTIVE - METHOD: In a recent article, it was stated that patients with a penicillin allergy history and negative skin tests to major and minor penicillin determinants are at a low risk of relapse (0-5%) when receiving a beta-lactam. In this paper, our Drug Allergy and Hypersensitivity Database, a cohort database, was used to demonstrate that this statement is false. Standardized European Network for Drug Allergy questionnaires, skin test and challenge procedures were followed.

RESULTS

One-thousand two-hundred and eighteen subjects, 69.8% of female, 51.7% of atopics, were included. 21.1% had a true beta-lactam allergy confirmed by skin tests (178, 69.3%) or by drug provocation (79, 30.7%). 17.4% of the patients with negative skin tests to major and minor penicillin determinants were positive for a beta-lactam.

CONCLUSION

In the diagnosis of beta-lactams allergy, if all skin tests are negative, skin tests with other determinants and provocation tests under strict surveillance are mandatory.

Recent advances in the diagnosis of drug allergy

PURPOSE OF REVIEW

The present review addresses the most recent literature regarding the diagnosis of drug hypersensitivity reactions, which can be classified as immediate or nonimmediate according to the time interval between the last drug administration and the onset. Immediate reactions occur within 1 h; nonimmediate ones occur after more than 1 h.

RECENT FINDINGS

Clinical and immunological studies suggest that type-I (IgE-mediated) and type-IV (cell-mediated) pathogenic mechanisms are involved in most immediate and nonimmediate reactions, respectively. New diagnostic tools, such as the basophil activation test and the lymphocyte activation test, have been developed and are under validation.

SUMMARY

In diagnosis, the patient's history is fundamental; the allergologic examination includes in-vivo and in-vitro tests selected on the basis of the clinical features. Prick, patch, and intradermal tests are the most readily available forms of allergy testing. Determination of specific IgE levels is still the most common in-vitro method for diagnosing immediate reactions. The sensitivity of allergologic tests is not 100%; in selected cases, therefore, provocation tests are necessary. The routine use of the basophil activation test and the lymphocyte activation test could increase the sensitivity of diagnostic work-ups, thus reducing the need for drug provocation tests.

Anaphylaxis during anaesthesia: diagnostic approach

Correct management of anaphylaxis during anaesthesia requires a multidisciplinary approach with prompt recognition and treatment of the acute event by the attending anaesthesiologist, and subsequent determination of the responsible agent(s) with strict avoidance of subsequent administration of all incriminated and/or cross-reacting compounds. However, correct identification of the causative compound(s) and safe alternatives is not always straightforward and, too often, not done. This review is not intended to discuss acute management of anaesthesia-related anaphylaxis but summarizes the major causes of anaphylaxis during anaesthesia and the diagnostic approach of this rare but potentially life-threatening complication. Apart from general principles about the diagnostic approach, history taking and importance of tryptase quantification, more specific confirmatory diagnostic procedures are organized on the basis of the major causes of perioperative anaphylactic reactions.

Continued need of appropriate betalactam-derived skin test reagents for the management of allergy to betalactams

Immediate allergic reactions to betalactams (BLs) are due to IgE antibodies that recognize the ring-derived penicilloyl determinant or side-chain structures of common BLs. The presence of specific IgE antibodies can be demonstrated by skin testing, the determination of specific IgE antibodies in sera or their binding to basophils with subsequent activation upon contact with penicillins in vitro. Skin tests are still the most sensitive technique followed by in vitro tests, which may sometimes yield useful complementary information. The diversity of the response to BLs has meant that in some instances, in addition to benzylpenicillin-derived determinants, testing for amoxycillin, cephalosporins or other BLs may also be required to establish the diagnosis. The recent withdrawal from the market of BL-derived materials for skin testing will have a serious effect on public health, resulting in a return to the pre-1960 era before these reagents became available. Because of their greater sensitivity, these skin tests cannot yet be replaced by in vitro tests. Furthermore, skin tests are the most readily available form of allergy testing for physicians. This paper reviews the results of skin tests in BL allergy and provides evidence for their continued need.

A comparison of the performance of two penicillin reagent kits in the diagnosis of beta-lactam hypersensitivity

BACKGROUND

Skin testing with penicilloyl polylysine (PPL) and minor determinant mixture (MDM) represents the first-line method for diagnosing beta-lactam hypersensitivity. However, in 2004, Allergopharma and Hollister-Stier announced their decision to stop the production of penicillin reagents (Allergopen and PrePen, respectively) within 1 year. Therefore, we decided to compare PPL and MDM from Allergopharma (Allergopen) with those from Diater (DAP).

METHODS

We skin-tested 195 subjects with both Allergopen and DAP reagents, as well as with other beta-lactams; 74 (group A) had had immediate reactions to beta-lactams and 74 (group B) nonimmediate reactions, while 47 (group C) underwent prophylactic tests.

RESULTS

One hundred two patients (52.3%) had positive skin tests; 29 (14.9%) were positive to PPL and/or MDM. Of the 102 skin-test-positive patients, 44 belonged to group A, 57 to B and 1 to C; the last was positive only to Allergopen PPL (PPL-A) and tolerated the benzylpenicillin challenge. Minor determinant mixture reagents produced identical results in the 148 patients of groups A and B, 22 (14.9%) of which were positive. Both PPL reagents produced negative results in 139 of these 148 patients and positive ones in 5; one subject was positive to DAP PPL (PPL-D) and negative to PPL-A, while three patients were positive to PPL-A and negative to PPL-D; two of the latter tolerated benzylpenicillin challenges.

CONCLUSIONS

Minor determinant mixture reagents produced identical results in all 195 patients. Results of skin testing with PPL reagents were concordant in 190 (97.4%) of them. Therefore, DAP reagents are a reliable alternative to Allergopen ones.