Multiple drug allergy syndrome: a distinct clinical entity

First-Line Antituberculosis Drug Challenge Reactions in Drug Reaction with Eosinophilia and Systemic Symptoms Syndrome in an HIV Endemic Setting

BACKGROUND

In high HIV prevalence settings, first-line antituberculosis drug (FLTD)-associated drug reaction with eosinophilia and systemic symptoms (DRESS) poses therapeutic challenges. A sequential and additive drug challenge (SADC) of FLTDs best identifies offending drug(s), avoids unnecessary exclusions, and optimizes reinitiation of nonoffending drugs. However, SADC-associated reaction complexities limit its utility.

OBJECTIVE

We aimed to describe the characteristics of patients with FLTD-associated DRESS, their treatment-limiting SADC reactions, and related outcomes.

METHODS

Patients hospitalized with FLTD-associated DRESS from 2013 to 2023 in a South African tertiary hospital and enrolled (retrospectively or prospectively) in an existing registry were eligible.

RESULTS

SADC was undertaken in 41 patients. Overall, 47 classifiable reactions occurred. 34/47 (72%) reactions in 29/41 (71%) patients were treatment-limiting and 12 of 41(29%) patients reinitiated FLTDs uneventfully. Fifteen single and 8 multiple drug reactors were identified. Rifampicin in 13 of 23(57%) reactors was the most common individual offender. Ethambutol was most frequently involved in multiple drug reactors. The median (interquartile range) time to a detectable reaction was 24(12-120) hours, 6 of 34(18%) being immediate (<6 hours). Itch (65%), eosinophilia (56%), fever (41%), atypical lymphocytosis (41%), rash (38%), transaminitis (32%), and facial edema (18%) singly or in combination were the most common features. Three reactions, 1 epidermal necrolysis and 2 liver derangements, were Common Terminology Criteria for Adverse Events grade 4 (life-threatening) events. No predictors of multiple drug reactivity were identified, but multiple reactors were hospitalized significantly longer, 125(100-134) days versus 60(45-80) days.

CONCLUSIONS

SADC optimizes FLTD reinitiation. However, timing, clinical presentation, and severity of SADC-associated reactions after FLTD-associated DRESS are markedly heterogeneous. Additionally, multiple drug reactors are a complex group that require longer hospitalization. There are no routine biomarkers available to distinguish true multiple drug hypersensitivity from nonspecific flare-ups and to guide long-term drug avoidance strategies.

Characterization, epidemiology and risk factors of multiple drug allergy syndrome and multiple drug intolerance syndrome: A systematic review

Background

Multiple drug allergy and multiple drug intolerance syndrome (MDAS/MDIS) labels are an impediment to clinical care and knowledge regarding these conditions is limited. This systematic review investigated the characterization, epidemiology, risk factors, clinical impact and pharmaco-economics of MDAS and MDIS.

Methods

Systematic literature search across 11 databases (01 January 2000-06 November 2020) for MDIS, MDAS and related terminology. Studies were reviewed for quality of evidence and risk of bias by employing Critical Appraisal Skills Programme cohort study checklist. A narrative synthesis approach facilitated by systematic textual descriptions, tabulation and thematic analysis was adopted.

Results

There was heterogeneity in terminology and methodology. Few studies applied standard drug allergy diagnostic methods. There is some evidence to suggest that multiple drug hypersensitivity syndrome (MDHS; i.e., confirmed allergies in MDAS) is a distinct clinical entity. Prevalence of MDIS and MDAS labels in unselected & selected populations varied between 2.1%-6.4% & 4.9%-90% and 1.2% & 0%-36% respectively. Reported risk factors included female gender, increasing age, body mass index, anxiety, depression, co-morbidities, concurrent allergies and increased healthcare utilization. Drugs commonly implicated were antibiotics and non-steroidal anti-inflammatory drugs. No studies relating to clinical impact and pharmaco-economics were found.

Conclusion

There is considerable burden of MDAS and MDIS labels. Data needs cautious interpretation as majority of studies described involved unverified labels. Despite this limitation and heterogeneity of studies, there is some evidence to suggest that MDHS is a distinct clinical entity. Well-designed multi-centre studies applying standardized terminology and diagnostic methodology are needed to gain further insight into these conditions.

Multiple drug allergies: Recommendations for perioperative management

Life-threatening hypersensitivity reactions are more likely to occur in patients with a history of allergy, atopy, or asthma. Hence, in a patient who presented with a history of multiple drug allergies (MDA), an allergological assessment should be performed prior to surgical procedure. Drug allergies, being one of the causes of catastrophic events occurring in the perioperative period, are of major concern to anesthesiologists. Neuromuscular blocking agents are regularly used during anesthesia and are one of the most common causes of perioperative anaphylaxis. They are estimated to be responsible for 50%-70% of perioperative hypersensitivity reactions. Antibiotics and latex represent the next two groups of drug allergy. Allergic reactions to propofol are rare with an incidence of 1:60,000 exposures. Although intraoperative drug anaphylaxis is rare, it contributes to 4.3% of deaths occurring during general anesthesia. These recommendations discuss pathophysiology of MDA, preoperative evaluation, and anesthesia considerations as well as the prevention and management of allergic reactions in anesthetized patients with a history of MDA.

Levels of cytokines in drug hypersensitivity

Introduction

Multiple drug intolerance is a serious complication of drug therapy and is an issue of allergology. The aim of the study was the investigation of cytokine status in patients with drug hypersensitivity and multiple drug hypersensitivity.

Material and methods

19 patients with multiple drug hypersensitivity, 34 patients with hypersensitivity to one drug, and 35 non-allergic subjects were involved. Only women were included in the study. A multiplex assay of 27 cytokines and chemokines was performed using xMap technology (Human Cytokine Panel I by Bio-Rad).

Results

Women with drug allergy revealed increased IL-2 levels (p < 0.05). In the case of the study of cytokine status in patients with multiple drug hypersensitivity, the new data revealed the prevalence of pro-inflammatory cytokine status with the participation of cytokines IL-17, IL-9, TNF-α, IP-10, and MIP-1.

Conclusions

Various immune response arms Th2, Th17, as well as macrophages were the determining factors in the cytokine balance that was found in patients with multiple drug hypersensitivity.

Multidrug intolerance in the treatment of hypertension: result from an audit of a specialized hypertension service

BACKGROUND

Hypertension as a cardiovascular disease risk factor continues to take a heavy toll on the population despite efforts with containment. Poor control, even among those on treatment, is part of the challenge and results from patient, physician and health system factors. When the problem resides at patient level, adherence is largely responsible. An entity defined as multidrug intolerance (MDI) is hardly considered. A situation when a patient is willing to adhere but is compelled otherwise could frustrate both patient and physician. Encountering a few such cases prompted the author to audit his specialized hypertension service in order to evaluate the burden of MDI and its associations.

METHODS

Between 7 May and 30 July 2016 (to cover a 12-week cycle which ensured all attendees were captured), all patients attending follow up for blood pressure control had their records evaluated for intolerance to three or more different classes of anti-hypertensives, which defines MDI. Their ages, sex, control state and co-morbidities were extracted from the records.

RESULTS

A total of 489 patients with hypertension were seen over the period; 271 (55.4%) of whom were women and 248 (50.7%) were uncontrolled. Overall 15 (3.1%) satisfied the definition of MDI; 10 women and 5 men. All the men with MDI were uncontrolled while 7 out of the 10 women were uncontrolled; with two having premenstrual syndrome as co-morbidity. A total of four patients (three men, one woman) had history suggesting allergy and two (one man, one woman) were on treatment for anxio-depressive illness.

CONCLUSION

MDI does occur in sub-Sahara African patients with hypertension and should be considered before describing hypertension as resistant or considering alternative treatments including device therapy. Staggering doses or trying different formulations could be of benefit.

Allergic Reactions in Hospitalized Patients With a Self-Reported Penicillin Allergy Who Receive a Cephalosporin or Meropenem

Background:

Cefepime and meropenem are used frequently in hospitalized patients for broad-spectrum empiric coverage, however, practitioners are often reluctant to prescribe these antibiotics for patients with a self-reported nonsevere, nontype I allergic reaction to penicillin.

Methods:

Retrospective review of electronic medical records of adults with a self-reported allergy to penicillin who received at least 1 dose of cefepime, ceftriaxone, cefoxitin, cephalexin, or meropenem to assess incidence and type of allergic reactions.

Results:

Of 175 patients included, 10 (6%) patients experienced an allergic reaction. The incidence for individual study drugs were cefepime 6% (6 of 96), meropenem 5% (3 of 56), cefoxitin 8% (1 of 13), ceftriaxone 0% (0 of 69), and cephalexin 0% (0 of 8). The majority of patients experienced a rash with or without pruritus and fever. Patients with a concomitant “sulfa” allergy (odds ratio [OR] 5.4, 95% confidence interval [CI] 1.4-21, P = .02) or ≥3 other drug allergies (OR 6.4, 95% CI 1.3-32, P = .025) were more likely to have an allergic reaction.

Conclusions:

In one of the largest retrospective reviews of hospitalized patients who received full dose therapy with cefepime, ceftriaxone, and meropenem, the incidence of allergic reactions was low and reactions were mild. Cefepime, ceftriaxone, and meropenem can be considered for use in patients with a self-reported nontype I penicillin allergy.

Evaluation of hypersensitivity reactions to nonsteroidal anti-inflammatory drugs according to the latest classification

BACKGROUND/AIM

The consensus document for hypersensitivity reactions to nonsteroidal anti-inflammatory drugs (NSAIDs) proposed by the European Network for Drug Allergy (ENDA) interest group (2011) was revised in 2013. We aimed to evaluate the usability of the latest NSAID hypersensitivity classification of ENDA.

METHOD

A total of 370 patients with a history of hypersensitivity reactions to NSAIDs among the 1250 outpatients referred for suspected drug allergy between July 2013 and June 2014 were evaluated, and 308 patients who were confirmed as having NSAID hypersensitivity were included in this study. After confirming the diagnosis, a single-blind placebo-controlled drug provocation test was performed with aspirin or diclofenac to categorize the patients according to the ENDA classification. The reactions not meeting the ENDA classification criteria were grouped as blended reactions.

RESULTS

Among the 308 patients (224 female, mean age 42.12 ± 13.24), the leading cause of hypersensitivity reactions was metamizol (30.5%) followed by aspirin (30.2%). The most common NSAID hypersensitivity subgroup was SNIUAA (46.4%) and the least common type was SNIDR (1.6%). Cross-reactivity was identified in 50.3% of the patients. In five patients (1.6%), the hypersensitivity reactions to NSAIDs did not meet the ENDA classification: Three patients experienced anaphylaxis with different NSAIDs, one patient encountered anaphylaxis with one NSAID and urticaria with other NSAIDs, and the last patient had angioedema with different NSAIDs.

CONCLUSION

The latest ENDA classification for NSAID hypersensitivity is generally a practical and useful instrument for clinicians. We only point out that anaphylaxis with different NSAIDs can be seen in a small group of patients.

Multiple drug intolerance syndrome: a large-scale retrospective study

Background

The term multiple drug intolerance syndrome (MDIS) has been used to describe patients who express adverse drug reactions to three or more drugs without a known immunological mechanism.

Objective

To identify patient factors that could increase the risk of MDIS.

Method

Inpatient records over a 5-year period were captured from an electronic prescribing system to identify patients with at least one documented drug allergy. Univariable and multivariable analyses were used to compare the rates of MDIS across age, sex, weight, ethnicity, history of atopy or psychological disorders, and previous admissions.

Results

A total of 25,695 patients had a documented drug intolerance, 4.9 % of whom had MDIS. MDIS was significantly more likely in women (p < 0.001), patients with multiple comorbidities (p < 0.001), and patients with previous hospital admissions (p < 0.001). With the exception of penicillin (p = 0.749), MDIS was more frequent in those with allergies to other drugs (p < 0.001).

Conclusion

MDIS was associated with female gender, multiple comorbidities, and previous hospital admissions. A documented allergy to penicillin did not increase the likelihood of MDIS.

Management of multiple drug allergies in children

Children with multiple drug allergies are likely to require treatment with one or more of the drugs to which they may have had a reaction, when there is no alternate effective drug available. Detailed review of their history and/or use of appropriate diagnostic studies will help determine the potential safety of readministering the desired drug as well as the method for its readministration, most likely in the form of a drug challenge or desensitization. A practical approach to the diagnosis and treatment of children with multiple drug allergies is described in this review.

Ferumoxytol: a silver lining in the treatment of anemia of chronic kidney disease or another dark cloud?

Intravenous iron therapy is pivotal in the treatment of anemia of chronic kidney disease to optimize the response of hemoglobin to erythropoiesis-stimulating agents. Intravenous iron use in patients with chronic kidney disease is on the rise. Recent clinical trial data prompting safety concerns regarding the use of erythropoiesis-stimulating agents has stimulated new US Food and Drug Administration label changes and restrictions for these agents, and has encouraged more aggressive use of intravenous iron. The currently available intravenous iron products differ with regard to the stability of the iron-carbohydrate complex and potential to induce hypersensitivity reactions. Ferumoxytol is a newer large molecular weight intravenous iron formulation that is a colloidal iron oxide nanoparticle suspension coated with polyglucose sorbitol carboxymethyl ether. Ferumoxytol has robust iron-carbohydrate complex stability with minimal dissociation or appearance of free iron in the serum, allowing the drug to be given in relatively large doses with a rapid rate of administration. Clinical trials have demonstrated the superior efficacy of ferumoxytol versus oral iron with minimal adverse effects. However, recent postmarketing data have demonstrated a risk of hypersensitivity that has prompted new changes to the product information mandated by the Food and Drug Administration. Additionally, the long-term safety of this agent has not been evaluated, and its place in the treatment of anemia of chronic kidney disease has not been fully elucidated.

Multiple drug intolerance syndrome: prevalence, clinical characteristics, and management

BACKGROUND

Population-based data on the demographics and clinical characteristics of patients with multiple unrelated drug class intolerances noted in their medical records are lacking.

OBJECTIVES

To provide population-based drug "allergy" incidence rates and prevalence, and to identify individuals with multiple drug intolerance syndrome (MDIS) defined by 3 or more unrelated drug class "allergies," and to provide demographic and clinical information on MDIS cases.

METHODS

Electronic medical record data from 2,375,424 Kaiser Permanente Southern California health plan members who had a health care visit and at least 11 months of health care coverage during 2009 were reviewed. Population-based drug "allergy" incidence rates and prevalence were determined for 23 unrelated medication classes.

RESULTS

On January 1, 2009, 478,283 (20.1%) health plan members had at least one reported "allergy." Individuals with a history of at least 1 "allergy" and females, in general, reported higher population-based new "allergy" incidence rates. Multiple drug intolerance syndrome was present in 49,582 (2.1%). The MDIS cases were significantly older, 62.4 ± 16.1 years; heavier, body mass index 29.3 ± 7.1; and likely to be female, 84.9%, compared with average health plan members. They had high rates of health care utilization, medication usage, and new drug "allergy" incidence. They sought medical attention for common nonmorbid conditions.

CONCLUSIONS

Multiple drug intolerance syndrome is in part iatrogenic. It is associated with overweight elderly women who have high rates of health care and medication usage. Urticarial syndromes only explain a small fraction of MDIS cases. Multiple drug intolerance syndrome is associated with anxiety, but not predominately with immunoglobulin E (IgE)-mediated allergy or life-threatening illness. Multiple drug intolerance syndrome can be managed by medication avoidance and judicious rechallenge.

Anesthesia in the patient with multiple drug allergies: are all allergies the same?

PURPOSE OF REVIEW

During the preoperative evaluation, patients frequently indicate 'multiple drug allergies', most of which have not been validated. Potential allergic cross-reactivity between drugs and foods is frequently considered as a risk factor for perioperative hypersensitivity. The aim of this review is to facilitate the recognition of risk factors for perioperative anaphylaxis and help the management of patients with 'multiple drug allergies' during the perioperative period.

RECENT FINDINGS

Neuromuscular blocking agents (NMBAs) and antibiotics are the most common drugs triggering perioperative anaphylaxis. Quaternary ammonium ions have been suggested to be the allergenic determinant of NMBAs. Even though the 'pholcodine hypothesis' has been suggested to explain the occurrence of NMBA-induced allergy, this concept remains unclear. Although many practitioners believe that certain food allergies present an issue with the use of propofol, there is no role to contraindicate propofol in egg-allergic, soy-allergic or peanut-allergic patients. IgE-mediated hypersensitivity has been reported with seafood and iodinated drugs, IgE-mediated hypersensitivity has been reported with seafood and iodinated drugs, but there is no cross-reactivity between them. The allergenic determinants have been characterized for fish, shellfish and povidone iodine and remain unknown for contrast agents.

SUMMARY

There are many false assumptions regarding drug allergies. The main goal of this article is to review the potential cross-reactivity among specific families of drugs and foods in order to facilitate the anesthetic management of patients with 'multiple drug allergies'.

Hypersensitivity reactions to contrast media: prevalence, risk factors and the role of skin tests in diagnosis--a cross-sectional survey

BACKGROUND

Hypersensitivity to contrast media (CMs) may be common and serious.

AIM

To evaluate the prevalence of CM hypersensitivity, risk factors associated with it and the role of skin testing in its diagnosis.

METHODS

A structured questionnaire was administered to patients who underwent computed tomography during a 1-year period. Skin tests with CMs, including skin prick tests (SPTs), intradermal tests (IDTs) and patch tests (PTs), were conducted on CM reactors (n = 24). Volunteers who tolerated CM exposure or had never been exposed to any CMs served as controls (n = 37).

RESULTS

A total of 1,131 patients (630 females and 501 males; mean age 55 ± 14.2 years) were enrolled in the study. The prevalence of historical and current CM reactors was 33/1,131 (2.92%) and 8/1,105 (0.72%), respectively. The skin was the most affected site, with mild to moderate reactions. Female gender, a history of doctor-diagnosed asthma, drug allergy, food allergy and psychiatric diseases were significant risk factors. The sensitivities of SPTs and early readings of IDTs in the diagnosis of immediate reactions were 0 and 20%, respectively, and the specificities were 94.6 and 91.4%, respectively. For early readings of IDTs, the positive predictive value (PPV) and negative predictive value (NPV) were 40 and 80%, respectively. For nonimmediate reactions, the sensitivities of delayed readings of IDTs and PTs were 14.3 and 25%, respectively; specificity was 100% for both tests. The PPV was 100% for both of these tests, and the NPVs were 85.4 and 82.4%, respectively.

CONCLUSIONS

Our findings are comparable with the incidence, profile and risk factors associated with CM hypersensitivity reported previously. Skin testing with CMs has a high specificity, but its role in diagnosis is limited due to low sensitivity.

Anaphylactic reaction to anakinra in a rheumatoid arthritis patient intolerant to multiple nonbiologic and biologic disease-modifying antirheumatic drugs

OBJECTIVE

To report a case of probable anaphylaxis due to anakinra in a patient with rheumatoid arthritis and multiple drug allergies.

CASE SUMMARY

A 46-year-old Indian female with rheumatoid arthritis demonstrated distinct adverse reactions to all commercially available anti-tumor necrosis factor therapies, sulfasalazine, and hydroxychloroquine. Over a 4-year period her disease remained active during therapy with methotrexate and prednisone. Biologics were added sequentially, with development of intolerable reactions, first to infliximab (urticarial rash, infusion reactions) after 3 doses, and then to etanercept (autoantibodies, worsening Raynaud's phenomenon, digital microinfarcts) after 1 year. Following 2 months of daily injections of anakinra, she experienced an immediate immunoglobulin E-mediated anaphylactic reaction within 20 minutes of an injection, as evidenced by positive testing to both anakinra and histamine with the skin prick method. The patient subsequently started adalimumab therapy, which was discontinued after the fourth dose due to the development of generalized hives.

DISCUSSION

The Naranjo probability scale demonstrated a probable relationship between anaphylaxis and anakinra in this patient. Although cases of anakinra-related hypersensitivity have been reported in patients in which therapy was interrupted and then reintroduced, to our knowledge, this is the first report of anaphylaxis with continuous therapy.

CONCLUSIONS

This unusual case of a patient with multiple drug allergies presents a difficult clinical scenario, which was unsuccessfully managed with multiple biologic therapies on a trial-and-error basis. In the future, pharmacogenetics may help to better identify individuals at risk for multiple drug reactions and preclude unnecessary exposure to potentially harmful therapeutic options in similar patients.

Coagulation cascade and fibrinolysis in patients with multiple-drug allergy syndrome

BACKGROUND

Previous studies have shown that patients with multiple-drug allergy syndrome (MDAS) frequently have positive autologous serum skin test results, similar to patients with chronic urticaria (CU). Recent investigations have found that patients with CU show signs of thrombin generation and activation of the tissue factor pathway of the coagulation cascade.

OBJECTIVE

To study thrombin generation and fibrinolysis in patients with MDAS.

METHODS

Nine patients with MDAS underwent autologous plasma skin testing (APST) and measurement of plasma prothrombin fragment F(1 + 2) and D-dimer levels. Furthermore, the basophil histamine-releasing activity of plasma from patients with MDAS was evaluated. Plasma samples from 74 healthy control subjects and 13 patients with CU were used as negative and positive controls, respectively.

RESULTS

All 9 patients with MDAS had positive APST results, and 7 showed elevated plasma levels of fragment F(1 + 2). In patients with MDAS, the median F(1 + 2) level (339 pmol/L; interquartile range [IQR], 250-401 pmol/L) significantly exceeded that in healthy controls (159 pmol/L; IQR, 123-196 pmol/L) (P = .001) but did not significantly differ from that in controls with CU (292 pmol/L; IQR, 182-564 pmol/L; P = .38). Plasma D-dimer levels were normal in all the patients with MDAS and were significantly lower than in controls with CU (P = .009). Finally, the histamine-releasing activity of plasma from patients with MDAS was significantly increased and correlated with F(1+ 2) levels (r = 0.68; P = .04).

CONCLUSION

Positive APST results and thrombin generation indicate a common physiopathologic background in MDAS and CU. The lower D-dimer levels suggest that fibrinolysis occurs less intensely in MDAS than in CU.

Multiple antibiotic allergy syndrome

Allergists/immunologists are commonly referred patients with histories of multiple antibiotic allergies and must determine what antibiotics they can safely use. This review covers articles published through September 2003. The history and definition of multiple antibiotic allergy syndrome are discussed. The clinical and laboratory evidence suggesting that certain individuals make allergic antibody to unrelated antibiotics is explored. A framework for dealing with this potentially vexing problem on a clinical level is developed. Areas that require additional research and development are outlined.

Distinct delayed T-cell response to beta-methasone and penicillin-G in the same patient

BACKGROUND

Multiple drug allergy syndrome is a clinical condition characterized by reactions against more than one different class of, both pharmacologically and structurally, unrelated drugs. Scanty data are available to date about a multiple drug delayed hypersensitivity syndrome. Our aim was to report the case of a delayed reaction to both beta-methasone (beta-MT) and penicillin-G (pen-G) occurring in the same patient, and analyse beta-MT- and pen-G-specific T-cell Lines (TCLs) with regard to their specificity, phenotype and cytokine profile.

METHODS

We generated two drug-specific TCLs from biopsies at the site of positive intradermal reactions, and analysed their immunophenotype, T-cell receptor Vbeta (TCR-Vbeta) domains expression and cytokine profile.

RESULTS

We demonstrated the specificity of the T cells isolated from positive intradermal test reactions to pen-G and beta-MT through the strict dose-dependent proliferation in response to drug-pulsed autologous antigen presenting cells. Fluorescence activated cell sorter (FACS) analysis revealed a predominance of CD4+ cells in the inflammatory cell infiltrate of intradermal test with beta-MT, while a predominance of CD8+ T cells in the site of delayed reaction to pen-G was found. The drug specific CD4+ and CD8+ T cells were heterogeneous, with regard to TCR-Vbeta usage. CD8+ pen-G-TCL displayed a preferential T helper 2 (Th2) profile, while a substantially heterogeneous pattern of cytokine production characterized specific beta-MT TCL.

CONCLUSION

The study describes the coexistence in the same patient of a delayed hypersensitivity to both penicillin G and beta-MT, driven, respectively, by pen-G-specificTh2-skewed CD8+ and beta-MT specificTh0 CD4+ T cells. This case further support the existence of a multiple drug allergy syndrome also for delayed hypersensitivity.

Immunoglobulin E binding determinants on beta-lactam drugs

PURPOSE OF REVIEW

Allergies to penicillins and cephalosporins remain an important clinical problem, but structural and immunochemical knowledge of the allergenic structures involved has tended to lag behind the heavy usage, consequent adverse reactions and introduction of new therapeutic members of these two families of antibiotics. Evidence of the increasing incidence of reactions to cephalosporins and to "minor" determinants of the beta-lactams is accumulating. Also, although numerous reports detail unique allergic recognitions of individual members of the two families, particularly the cephalosporins, information remains predominantly clinical. The present review summarizes the most recent advances in studies of structural aspects of beta-lactams as allergens.

RECENT FINDINGS

For the cephalosporins, a pyrazinone allergenic degradation product of cefaclor and cephalexin has been identified and characterized. The widely used cephalosporin cephalothin was shown to cross-react allergenically with benzylpenicillin and the common cross-reacting structure was identified. The fine structural features on the amoxicillin molecule recognized by antibodies that distinguish "major" and "minor" determinants were identified, and steric factors were used to explain antibody recognition of the amoxicillin determinants. A recent study elucidated the molecular basis of some cases of the multiple drug allergy syndrome and its relationship to beta-lactam allergy.

SUMMARY

Findings of the type described in the present review provide fundamental insights into the nature and size of antigenic determinants on "small" molecules such as drugs and other chemicals. At the clinical level, such structure/activity findings have implications for our understanding of drug allergenic cross-reactions, for selection for therapy of an appropriate member from a family of structurally related drugs and, ultimately, for desensitization of drug-allergic patients.