Deconstructing adverse reactions to Amoxicillin-Clavulanic Acid: the importance of time of onset.

BACKGROUND: Amoxicillin-clavulanic acid (AX-CL) is the most consumed betalactam antibiotic worldwide. We aimed to establish the different phenotypes of betalactam allergy in those referring a reaction with AX-CL and to investigate the differences between immediate and non-immediate onset. METHODS: Cross-sectional retrospective study performed at Hospital Clínico San Carlos (HCSC) and Hospital Regional Universitario de Málaga (HRUM) in Spain. Patients reporting reactions with AX-CL who completed the allergy workup between 2017 and 2019 were included. Data of reported reaction and allergy workup were collected. Reactions were classified as immediate and non-immediate with 1hour cut-off point. RESULTS: We included 372 patients (HCSC 208, HRUM 164). There were 90 (24.2%) immediate, 252 (67.7%) non-immediate reactions, and 30 (8.1%) with unknown latency. Allergy to betalactams was ruled-out in 266 (71.5%) and confirmed in 106 patients (28.5%). The final main diagnosis in the overall population were allergy to aminopenicillins (7.3%), to CL (7%), to penicillin (6.5%) and to betalactams (5.9%). Allergy was confirmed in 77.2% and 14.3% of immediate and non-immediate reactions respectively, with a relative risk of 5.06 (95%CI 3.64-7.02) of an allergy diagnosis in those reporting immediate reactions. Only 2/54 patients with late-positive intradermal test (IDT) to CL were diagnosed of CL allergy. CONCLUSION: Allergy diagnosis was confirmed in a minority of the whole study population, but 5 times more frequently in those reporting immediate reactions, making this classification useful in risk stratification. Late-positive IDT for CL has no diagnostic value and its late reading could be retrieved from the diagnosis work-up.

Polymorphisms in eicosanoid-related biosynthesis enzymes associated with acute urticaria/angioedema induced by nonsteroidal anti-inflammatory drug hypersensitivity.

BACKGROUND: Nonsteroidal anti-inflammatory drugs (NSAIDs) are the main triggers of drug hypersensitivity, with NSAID-induced acute urticaria/angioedema (NIUA) the most frequent phenotype. NSAID hypersensitivity is caused by cyclooxygenase 1 inhibition, which leads to an imbalance in prostaglandin (PG) and cysteinyl leukotriene (CysLT) synthesis. As only susceptible individuals develop NSAID hypersensitivity, genetic factors are believed to be involved; however, no study has assessed the overall genetic variability of key enzymes in PG and CysLT synthesis in NSAID hypersensitivity. OBJECTIVES: To evaluate simultaneously variants in the main genes involved in PG and CysLT biosynthesis in NIUA. METHODS: Two independent cohorts of patients were recruited in Spain, alongside NSAID-tolerant controls. The discovery cohort included only patients with NIUA; the replication cohort included patients with NSAID-exacerbated respiratory disease (NERD). A set of tagging single-nucleotide polymorphisms (tagSNPs) in PTGS1, PTGS2, ALOX5 and LTC4S was genotyped using mass spectrometry coupled with endpoint polymerase chain reaction. RESULTS: The study included 1272 individuals. Thirty-five tagSNPs were successfully genotyped in the discovery cohort, with three being significantly associated after Bonferroni correction (rs10306194 and rs1330344 in PTGS1; rs28395868 in ALOX5). These polymorphisms were genotyped in the replication cohort: rs10306194 and rs28395868 remained associated with NIUA, and rs28395868 was marginally associated with NERD. Odds ratios (ORs) in the combined analysis (discovery and replication NIUA populations) were 1·7 for rs10306194 [95% confidence interval (CI) 1·34-2·14; Pcorrected = 2·83 × 10-4 ) and 2·19 for rs28395868 (95% CI 1·43-3·36; Pcorrected = 0·002). CONCLUSIONS: Variants of PTGS1 and ALOX5 may play a role in NIUA and NERD, supporting the proposed mechanisms of NSAID-hypersensitivity and shedding light on their genetic basis.

Clinical Practice Guidelines for Diagnosis and Management of Hypersensitivity Reactions to Quinolones.

The consumption of quinolones as first-line treatment has increased in recent years, leading to an increase in the incidence of hypersensitivity reactions (HSRs) to this antibiotic group. Both diagnosis and management of HSRs to quinolones are complex and controversial. These practical guidelines aim to provide recommendations for effective clinical practice. The recommendations were drafted by an expert panel that reviewed the literature regarding HSRs to quinolones and analyzed controversies in this area. Most HSRs to quinolones are immediate and severe. The risk for HSRs is higher in patients who report allergy to ß-lactams, moxifloxacininduced anaphylaxis, and immediate reactions than in patients who report reactions to quinolones inducing other symptoms. The usefulness of skin tests in diagnosing HSRs to quinolones is controversial, with sensitivity and specificity varying between studies. Most in vitro tests are produced in-house, with no validated commercial options. The basophil activation test has proven useful for diagnosing immediate reactions, albeit with diverse results regarding sensitivity. Drug provocation testing is currently the gold standard for confirming or excluding the diagnosis and for finding safe alternatives, although it is contraindicated in patients with severe reactions. Cross-reactivity between quinolones has proven controversial in several studies, with the lowest cross-reactivity reported for levofloxacin. Desensitization may be considered in allergy to quinolones when no other alternatives are available.

Hypersensitivity Reactions to Cancer Chemotherapy: Practical Recommendations of ARADyAL for Diagnosis and Desensitization.

Rapid drug desensitization has enabled first-line therapies in patients with drug hypersensitivity reactions to chemotherapeutic drugs including monoclonal antibodies. Desensitization is a safe and highly effective procedure, not only for IgE-mediated reactions, but also for those mediated by non-IgE mechanisms. The likelihood of breakthrough reactions during desensitization is low, and most are mild; in fact, moderate-to-severe reactions are infrequent. In this document, 16 allergy departments belonging to the Spanish research network ARADyAL present a review of the available scientific evidence and provide general guidelines for the diagnosis and management of drug hypersensitivity reactions to chemotherapeutic drugs and monoclonal antibodies. Emphasis is placed on the desensitization procedure.

Statement of the Spanish Society of Allergology and Clinical Immunology on Provocation Tests With Aspirin/Nonsteroidal Anti-inflammatory Drugs.

Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used throughout the world. They are frequently involved in hypersensitivity reactions, which range from local or mild reactions to systemic and severe reactions. Consequently, it is necessary to perform an exhaustive study of patients in order to make an accurate diagnosis, search for safe procedures in the case of severe reactions, and identify alternative treatment options. Various guidelines and protocols address the management of hypersensitivity to NSAIDs, although these vary widely from country to country. The Committees of Asthma, Rhinoconjunctivitis, and Drug Allergy of the Spanish Society of Allergy and Clinical Immunology (SEAIC) propose the present position statement on available options for provocation testing with aspirin/NSAIDs. This document is the fruit of an exhaustive review of current evidence and is based on recent publications addressing the diagnosis of patients with hypersensitivity to NSAIDs and on a consensus-oriented discussion among a group of experts from the SEAIC. The main objective was to draft an easy-toread, practical guideline for health care professionals in specialist areas who assess and manage patients with suspected hypersensitivity to NSAIDs. Furthermore, indications, contraindications, and procedures for oral, bronchial, and nasal provocation tests with aspirin/NSAIDs have been updated.

Spanish Guidelines for Diagnosis, Management, Treatment, and Prevention of DRESS Syndrome.

BACKGROUND AND OBJECTIVE: Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is a complex multisystemic severe drug hypersensitivity reaction whose diagnosis and management are troublesome. DRESS syndrome requires management by various specialists. The correct identification of the culprit drug is essential to ensure safe future therapeutic options for the patient. There are no previous Spanish guidelines or consensus statements on DRESS syndrome. Objective: To draft a review and guidelines on the clinical diagnosis, allergy work-up, management, treatment, and prevention of DRESS syndrome in light of currently available scientific evidence and the experience of experts from multiple disciplines. METHODS: These guidelines were drafted by a panel of allergy specialists from the Drug Allergy Committee of the Spanish Society of Allergy and Clinical Immunology (SEAIC), together with other medical specialists involved in the management of DRESS syndrome and researchers from the PIELenRed consortium. A review was conducted of scientific papers on DRESS syndrome, and the expert panel evaluated the quality of the evidence of the literature and provided grades of recommendation. Whenever evidence was lacking, a consensus was reached among the experts. RESULTS: The first Spanish guidelines on DRESS syndrome are now being published. Important aspects have been addressed, including practical recommendations about clinical diagnosis, identification of the culprit drug through the Spanish pharmacovigilance system algorithm, and the allergy work-up. Recommendations are provided on management, treatment, and prevention. Algorithms for the management of DRESS in the acute and recovery phases have been drawn up. Expert consensus-based stepwise guidelines for the management and treatment of DRESS syndrome are provided.

Accuracy of the Diagnosis of Allergic Reactions in the Emergency Department.

BACKGROUND AND OBJECTIVE: Suspicion of an acute allergic reaction is a common reason for attending the emergency department (ED). However, there are few comparisons between the initial diagnosis of suspected allergic reaction made in the ED with the definitive diagnosis made subsequently in the allergy department (AD). Objective: To compare details of the initial diagnosis made in the ED relating to allergy with the final diagnosis made in the AD. METHODS: Patients attending the ED of 2 hospitals with suspected allergic reactions were prospectively enrolled based on key words. A certified allergy specialist reviewed the ED records of these patients and, if these were suggestive of an allergic reaction, the patients were scheduled for further evaluation at the allergy clinic. RESULTS: In total, 2000 patients were enrolled between April 2013 and October 2015. Of these, 1333 passed the initial assessment and underwent further evaluation. Of the 1333 patients, 528 underwent an allergological study, and 206 were confirmed as being allergic. With respect to drug allergy, nonsteroidal anti-inflammatory drugs were the most common triggers, followed by ß-lactams; in food allergy, plant-based foods were the most common. Only 16.4% of patients confirmed as having anaphylaxis in the AD were initially diagnosed with the condition in the ED. CONCLUSION: Of the 528 patients who finally underwent the full allergological study, fewer than half were confirmed as allergic. Moreover, anaphylaxis appears to be underdiagnosed in the ED. Better communication between the ED and the AD is necessary to improve the diagnosis and management of these patients.

Practical Guidelines for Perioperative Hypersensitivity Reactions.

Perioperative hypersensitivity reactions constitute a first-line problem for anesthesiologists and allergists. Therefore, hospitals should have a consensus protocol for the diagnosis and management of these reactions. However, this kind of protocol is not present in many hospitals, leading to problems with treatment, reporting of incidents, and subsequent etiological diagnosis. In this document, we present a systematic review of the available scientific evidence and provide general guidelines for the management of acute episodes and for referral of patients with perioperative hypersensitivity reactions to allergy units. Members of the Drug Allergy Committee of the Spanish Society of Allergy and Clinical Immunology (SEAIC) have created this document in collaboration with members of the Spanish Anesthesia Society (SEDAR). A practical algorithm is proposed for the etiologic diagnosis, and recommendations are provided for the management of hypersensitive patients.

Natural evolution in patients with nonsteroidal anti-inflammatory drug-induced urticaria/angioedema.

BACKGROUND: Nonsteroidal anti-inflammatory drugs (NSAIDs) are the most frequent triggers of drug hypersensitivity with NSAIDs-induced urticaria/angioedema (NIUA) the most common phenotype. Loss of hypersensitivity has been reported for IgE-mediated reactions; however, it has not been assessed in nonimmunological reactions such as NIUA. We evaluated NSAID-hypersensitivity over time in NIUA patients. METHODS: Patients confirmed as NIUA by positive drug provocation test (DPT) with acetylsalicylic acid (ASA) during 2005-2012 (V1) were included (n=38). Subjects were prospectively re-evaluated by DPT with ASA/other NSAIDs at two time points between 2013 and 2015 (V2 and V3). Atopy was assessed by skin prick test (SPT) using inhalant and food allergens. RESULTS: Patients were evaluated at V1 and re-evaluated after 60 months (V2; IR:48-81) and a further 18 months (V3; IR:14-24). At V2, the majority (24; 63.15%) tolerated ASA and other NSAIDs (Group A) while 14 (36.84%) still reacted (Group B). At V3, all Group A patients remained tolerant; all Group B patients remained hypersensitive. The number of previous episodes reported at V1 and the percentage of reactions induced by ASA/ibuprofen were significantly lower in Group A (P=.005 and P=.006, respectively). Group A patients developed tolerance 72 months (IR:45-87) after their last evaluated reaction (V1); this interval was shorter in nonatopics (P=.003), patients who experienced reactions over 1 hour after NSAIDs administration (P=.001), and those who experienced isolated urticaria after NSAID intake (P=.024). CONCLUSIONS: NIUA patients may develop tolerance to NSAIDs over time, a process that seems to be influenced by atopy and type of clinical reaction.

Update on the Genetic Basis of Drug Hypersensitivity Reactions.

Drug hypersensitivity reactions (DHRs) are unpredictable, complex responses to medicines in predisposed individuals. They represent a major health problem owing to the number of patients affected and the severity of the clinical conditions they can induce. In addition to environmental factors, the underlying mechanisms of DHRs are also influenced by genetic factors, although considerable gaps remain in our knowledge. Therefore, further study of the genetics of DHRs is necessary to shed light on their underlying mechanisms. In this manuscript, we provide an update on the genetic basis of the most frequent types of DHRs, including those mediated by immunological and nonimmunological mechanisms. For the first group, we will focus on immediate reactions to ß-lactam antibiotics, which are associated mainly with the IgE pathway (IL13, IL4R, LGALS3, and NOD2) and antigen presentation (HLA-DRA), and nonimmediate reactions to allopurinol, anticonvulsants, antibiotics, and antiretrovirals, which are often associated with polymorphisms in the HLA system. For the second group, we will focus on nonsteroidal anti-inflammatory drugs, which are mostly associated with genetic variants in enzymes and receptors from the arachidonic acid pathway (eg, ALOX5, ALOX5AP, PTGDR, and CYSLTR1). The information provided here will be of interest for medical practitioners from a range of disciplines who come across these reactions in their clinical practice, as well as for allergologists.

Immediate Reactions to More Than 1 NSAID Must Not Be Considered Cross-Hypersensitivity Unless Tolerance to ASA Is Verified.

BACKGROUND AND OBJECTIVES: Individuals who develop drug hypersensitivity reactions (DHRs) to chemically unrelated nonsteroidal anti-inflammatory drugs (NSAIDs) are considered cross-hypersensitive. The hallmark for this classification is that the patient presents a reaction after intake of or challenge with acetylsalicylic acid (ASA). Whether patients react to 2 or more NSAIDs while tolerating ASA remains to be studied (selective reactions, SRs). Objective: To identify patients with SRs to 2 or more NSAIDs including strong COX-1 inhibitors. METHODS: Patients who attended the Allergy Service of Hospital Infanta Leonor, Madrid, Spain with DHRs to NSAIDs between January 2011 and December 2014 were evaluated. Those with 2 or more immediate reactions occurring in less than 1 hour after intake were included. After confirming tolerance to ASA, the selectivity of the response to 2 or more NSAIDs was demonstrated by in vivo and/or in vitro testing or by controlled administration. RESULTS: From a total of 203 patients with immediate DHRs to NSAIDs, 16 (7.9%) met the inclusion criteria. The patients presented a total of 68 anaphylactic or cutaneous reactions (mean [SD], 4.2 [2.1]). Most reactions were to ibuprofen and other arylpropionic acid derivatives and to metamizole. Two different NSAIDs were involved in 11 patients and 3 in 5 patients. CONCLUSIONS: Patients with NSAID-induced anaphylaxis or urticaria/angioedema should not be considered cross-hypersensitive unless tolerance to ASA is verified.

A non-synonymous polymorphism in galectin-3 lectin domain is associated with allergic reactions to beta-lactam antibiotics.

Genetic predictors of beta-lactam (BL) allergy are mostly related to Immunoglobulin E (IgE) synthesis and atopy. Despite this context, little attention has been devoted to genes of IgE/FcɛRI pathway, such as galectin-3, a ß-galactoside-binding lectin, which binds to IgE. We evaluated the association of LGALS3 polymorphisms with BL allergy in 395 Spanish and 198 Italian cases, compared with 310- and 339-matched controls, respectively. The rs11125 predicted BL allergy with an odds ratio of 4.0 in Spanish population (P<0.0001). This association was replicated with an odds ratio of 5.1 in Italian population (P<0.0001); rs11125 predicted also increased serum level of total IgE in Spanish controls. These data are consistent with the predicted deleterious influence of Gln>His substitution produced by rs11125 on galactose-binding activity of galectin-3. In conclusion, LGALS3 is the strongest genetic predictor of BL allergy reported so far. This association reflects the influence of genes of IgE/FcɛRI pathway in this pathology.

Immediate hypersensitivity reactions to ibuprofen and other arylpropionic acid derivatives.

BACKGROUND: Although ibuprofen and other arylpropionic acid derivatives (APs) are the most common medicines involved in hypersensitivity drug reactions (HDRs) to NSAIDs, no patient series studies have been performed regarding immediate selective reactions (SRs) to these drugs. OBJECTIVE: To characterize patients with immediate selective HDRs to ibuprofen and other APs through clinical history and challenge. METHODS: Subjects who developed an HDR to APs less than 1 h after drug intake were included. Tolerance to aspirin was assessed and challenge was performed with ibuprofen in all cases, and additionally with the culprit drug (if different) in those patients that tolerated ibuprofen. Serum tryptase levels and tryptase immunohistochemical staining in skin biopsies were also assessed in some patients with a positive DPT to ibuprofen. RESULTS: From a total of 245 patients with a confirmed history of HDRs to APs, 17% were classified as selective immediate hypersensitivity reactors by both clinical history and challenge. A selective response to naproxen and dexketoprofen with tolerance to ibuprofen was found in 16 of 20 cases. Significant differences in serum tryptase levels were observed between 2 and 24 h in the 11 cases that were studied further. CONCLUSIONS: Within the group of patients with HDRs to NSAIDs, APs can induce immediate SRs. Within this group, selective responses to a single drug or responders to several APs may exist, suggesting potential immunological cross-reactivity.

The Genetics of Drug Hypersensitivity Reactions.

DHRs are induced by various mechanisms and encompass a heterogeneous set of potentially life-threatening clinical entities. In addition to environmental effects, individual factors play a key role in this intricate puzzle. However, despite commendable efforts in recent years to identify individual predisposing factors, our knowledge of the genetic basis of these reactions remains incomplete. In this manuscript, we summarize current research on the genetics of DHRs, focusing on specific immune-mediated reactions (immediate and nonimmediate) and on pharmacologically mediated reactions (cross-intolerance to nonsteroidal anti-inflammatory drugs). We also provide some thoughts on potential technological approaches that would help us to decipher the molecular mechanisms underlying DHRs. We believe this manuscript will be of interest not only for allergists and basic researchers in the field, but also for clinicians from various areas of expertise who manage these reactions in their clinical practice.

Initial immunological changes as predictors for house dust mite immunotherapy response.

BACKGROUND: Although specific immunotherapy is the only aetiological treatment for allergic disorders, the underlying mechanisms are not fully understood. Specific immunotherapy induces changes in lymphocyte Th subsets from Th2 to Th1/Treg. Whether differences in immunological patterns underlie patient response to immunotherapy has not yet been established. OBJECTIVES: We studied the immunological changes occurring during a 1-year period of Dermatophagoides pteronyssinus (DP) immunotherapy and their relation with clinical outcome. METHODS: We included 34 patients with DP allergy who received subcutaneous specific immunotherapy (SCIT) for 1 year. Following treatment, patients were classified as responders or non-responders. Fourteen allergic subjects who did not receive SCIT were included as controls. Peripheral blood was obtained at 0, 1, 3, 6 and 12 months and cultured with nDer p 1. Phenotypic changes, cytokine production and basophil response were analysed by flow cytometry; transcription factors were measured by mRNA quantification. Serum immunoglobulin levels were also measured. RESULTS: After 1 year of SCIT, 82% of cases showed improved symptoms (responders). Although increases in sIgG4 were observed, BAT reactivity was not modified in these patients. Increases in T-BET/FOXP3 as well as nDer p 1-specific Th1/Treg frequencies were also observed, along with a decrease in Th2, Th9 and Th17. These changes corresponded to changes in cytokine levels. CONCLUSION: Patients who respond well to DP-SCIT show immunological differences compared to non-responders. In responders, basal differences include a lower frequency of Th1 and higher frequencies of Th2, Th9 and Th17 cells. After 1 year of treatment, an increased production of sIgG4 was observed in responders, along with a change in Th2 response towards Th1/Treg.

Hypersensitivity to Nonsteroidal Anti-inflammatory Drugs in Children and Adolescents: Cross-Intolerance Reactions.

Nonsteroidal anti-inflammatory drugs (NSAIDs) are used worldwide and are responsible for several types of drug hypersensitivity reactions (DHRs) in all age groups. The 2 major groups of DHRs to NSAIDs are those induced by immunological mechanisms (selective reactions) and those where inflammatory mediators are released through activation of the prostaglandin-leukotriene pathway without specific immunological recognition (cross-intolerance). In the present review, we focus on cross-intolerance reactions, which are the most frequent DHRs and are becoming a topic of major interest in children and adolescents. Paracetamol and ibuprofen are the drugs that most frequently cause DHRs in children; other NSAIDs are responsible for reactions in adolescents. In vivo and in vitro tests are of limited diagnostic value, with some exceptions for the less common selective reactions. In cross-intolerance, the clinical history and controlled administration are in many instances the only way to establish a diagnosis and look for alternatives. The clinical history is diagnostic when consistent symptoms occur repeatedly after exposure to NSAIDs with different chemical structures. Cutaneous and respiratory symptoms often co-occur in young children. The natural history of these reactions in children is unknown, and some patients can develop tolerance over time. Atopy remains a major risk factor for cross-intolerant reactions. The increasing interest in hypersensitivity to NSAIDs with improvements in patient phenotyping and the information provided by pharmacogenetics will improve our understanding and management of these reactions in the near future.

Hypersensitivity Reactions to Nonsteroidal Anti-inflammatory Drugs in Children and Adolescents: Selective Reactions.

Nonsteroidal anti-inflammatory drugs (NSAIDs) are used throughout the world to treat pain and inflammation; however, they can trigger several types of drug hypersensitivity reactions (DHRs) in all age groups. Although most such reactions occur through activation of the leukotriene pathway without specific immunological recognition (cross-intolerance), a significant number of DHRs to NSAIDs are due to immunological mechanisms (selective reactions [SRs]). SRs are thought to be induced by specific IgE antibodies or by T cells. In this manuscript, we focus on SRs, which are of great concern in children and adolescents and comprise a heterogeneous set of clinical pictures ranging from mild entities such as urticaria/angioedema to potentially life-threatening conditions such as Stevens-Johnson syndrome/toxic epidermal necrolysis. Paracetamol and ibuprofen are the most frequent elicitors of IgE-mediated SRs, although pyrazolones have also been implicated. T cell-mediated reactions are infrequent in children but have been associated with ibuprofen, naproxen, and dipyrone. In this review, we analyze the available literature on SRs in children and adolescents, with emphasis on epidemiological data, mechanisms, and drugs involved, as well as on diagnostic procedures.

NSAID-induced urticaria/angioedema does not evolve into chronic urticaria: a 12-year follow-up study.

BACKGROUND: Nonsteroidal anti-inflammatory drugs (NSAIDs) are the most frequent medicaments involved in drug hypersensitivity reactions, with NSAID-induced urticaria/angioedema (NIUA) being the most frequent clinical entity. The natural evolution of NIUA has been suggested to lead to chronic urticaria (CU) in an important proportion of patients, such that NIUA may therefore precede CU. Our aim was to verify whether these entities are related by following up a large cohort of patients with NIUA as well as a control group over a long period of time. METHODS: The study comprised three groups: (i) patients with a confirmed history of NIUA (more than two episodes with at least two different NSAIDs or positive drug provocation tests), (ii) patients with more than two episodes of urticaria/angioedema to a single NSAID with good tolerance to a strong COX-1 inhibitor and/or evidence by in vivo tests supporting specific IgE antibodies to the drug (single NSAID-induced urticaria/angioedema, SNIUA), and (iii) controls who tolerated NSAIDs. All cases in the three groups were followed up over a period of 12 years. RESULTS: There were 190 patients with NIUA (64.6% female; mean age 43.71 ± 15.82 years, 110 with SNIUA, and 152 controls. At the 12-year evaluation, 12 patients with NIUA (6.15%) had developed CU over a 1- to 8-year period. Similar proportions were seen in SNIUA and controls. CONCLUSIONS: Nonsteroidal anti-inflammatory drugs-induced urticaria/angioedema does not seem to precede the onset of CU over the medium term. Further research including a longer follow-up is necessary to verify this observation.

Trends in hypersensitivity drug reactions: more drugs, more response patterns, more heterogeneity.

Hypersensitivity drug reactions (HDRs) vary over time in frequency, drugs involved, and clinical entities. Specific reactions are mediated by IgE, other antibody isotypes (IgG or IgM), and T cells. Nonspecific HDRs include those caused by nonsteroidal anti-inflammatory drugs (NSAIDs). beta-Lactams--the most important of which are amoxicillin and clavulanic acid--are involved in specific immunological mechanisms. Fluoroquinolones (mainly moxifloxacin, followed by ciprofloxacin and levofloxacin) can also induce HDRs mediated by IgE and T cells. In the case of radio contrast media, immediate reactions have decreased, while nonimmediate reactions, mediated by T cells, have increased. There has been a substantial rise in hypersensitivity reactions to antibiotics and latex in perioperative allergic reactions to anesthetics. NSAIDs are the most frequent drugs involved in HDRs. Five well-defined clinical entities, the most common of which is NSAID-induced urticaria/angioedema, have been proposed in a new consensus classification. Biological agents are proteins including antibodies that have been humanized in order to avoid adverse reactions. Reactions can be mediated by IgE or T cells or they may be due to an immunological imbalance. Chimeric antibodies are still in use and may have epitopes that are recognized by the immune system, resulting in allergic reactions.

Practical guidelines for diagnosing hypersensitivity reactions to nonsteroidal anti-inflammatory drugs.

Nonsteroidal anti-inflammatory drugs (NSAIDs) are the drugs most frequently involved in hypersensitivity reactions. These reactions include various clinical entities with different mechanisms leading to the release of inflammatory mediators. Characterization of patients based on clinical manifestations and suspected underlying mechanisms is critical for implementation of adequate diagnostic procedures and patient management. Our objectives were to prepare a systematic review of available scientific evidence and to provide general guidelines for the diagnosis and management of patients with hypersensitivity reactions to NSAIDs. We also propose a practical algorithm for the diagnosis of specific types of hypersensitivity to NSAIDs and provide recommendations for the management of hypersensitive patients.