Paracetamol (Acetaminophen)-associated SJS, TEN, AGEP, and DRESS Syndromes - A Narrative Review

INTRODUCTION

Paracetamol (Acetaminophen) is a very common OTC drug that is found in more than 200 OTC products sold as pain, cough and cold remedies. Paracetamol is commonly used as an antipyretic to reduce fever and as an alternative to Non-steroidal anti-inflammatory drugs (NSAIDs) that are contraindicated in certain patients to relieve mild-moderate pain.

OBJECTIVE

This review article focuses on SJS, TEN, SJS/TEN overlap, AGEP, and DRESS syndromes associated with the use of paracetamol or paracetamol-containing products.

METHODS

To find published articles relevant to paracetamol-associated SJS, TEN, AGEP, and DRESS, we searched the online databases Medline/Pubmed/PMC, Google Scholar, Science Direct, Ebsco, Scopus, Web of Science, Embase, and reference lists using keywords like Stevens-Johnson Syndrome, Acetaminophen, Paracetamol, Toxic epidermal necrolysis, Acute generalized exanthematous pustulosis, Drug reaction with eosinophilia and systemic symptoms.

RESULTS

The paracetamol-associated SJS, TEN, SJS/TEN overlap, AGEP, and DRESS syndromes have been identified by a number of publications.

CONCLUSION

When evaluating drug-induced hypersensitivity skin reactions, healthcare professionals, including prescribers, pharmacists, and others, should be aware of this rare risk. Patients who exhibit signs and symptoms of paracetamol-associated hypersensitivity should be referred to physicians by pharmacists for further treatment. At the first sign of a skin rash or other hypersensitivity reaction while taking paracetamol, patients should be told to stop taking it and see a doctor right away.

An Update on Nonsteroidal Anti-Inflammatory Drug-Induced Urticaria

BACKGROUND

Hypersensitivity reactions to non-steroidal anti-inflammatory drugs (HR-NSAIDs) are common adverse events related to the widespread use of over-the-counter NSAIDs for the treatment of a variety of inflammatory conditions. Urticaria is the most commonly reported immediate cutaneous clinical sign of HR-NSAIDs, but it can be a manifestation of pathophysiologically different clinical entities that require different therapeutic strategies. The aim of this study is to ease the identification of the correct phenotype of HR-NSAIDs in patients reporting urticaria associated with the intake of NSAIDs and provide updated information about their diagnosis and management.

METHODS

The study is a narrative review conducted by collecting the most relevant and up-todate data related to the classification, pathophysiology, severity, and prognosis of NSAID hypersensitivity reactions. PubMed and Embase scientific databases were used as search engines to select relevant articles.

RESULTS

Patients developing HR-NSAIDs can be divided into two categories: selective responders (SR), who develop reactions after the administration of a single specific NSAID due to an underlying IgE or T-cell mediated hypersensitivity mechanism, or cross-intolerant (CI), who develop reactions to more than one chemically unrelated NSAIDs due to abnormalities in the biochemical pathways related with prostaglandin metabolism, independently from an underlying immunological mechanism. Five major different categories of HR-NSAIDs have been identified: NSAIDs-exacerbated cutaneous disease (NECD), NSAIDs-induced urticaria/angioedema with/without respiratory and systemic symptoms of anaphylaxis (NIUAA), and NSAIDsexacerbated respiratory disease (NERD), which are developed by CI patients, and single NSAIDs-induced urticaria, angioedema and/ or anaphylaxis (SNIUAA) and single NSAIDsinduced delayed hypersensitivity reactions (SNIDHR), which are developed by CI patients. In vivo and in vitro diagnostic tests have rarely been shown to be reliable in all these entities and therefore are not routinely used in clinical practice. The management in SR patients consists of strict avoidance of the culprit drug, while for cross-intolerance reactions oral tolerance tests with safe alternative drugs (e.g. weak COX-1 inhibitors or selective COX-2 inhibitors) can be performed.

CONCLUSION

HR-NSAIDs are being observed with increasing frequency, however, the pathogenesis behind some NSAIDS-associated clinical entities is still unclear. Diagnosis is mostly based on a thorough clinical history and confirmed by a drug challenge test. Clinical management is based on strict avoidance and use of alternative tolerated medications. Overall, all therapeutic decisions depend on the correct identification of the type of reaction the patient experienced.

An Unusual IgE-Mediated Hypersensitivity: Two Case Reports of Paracetamol Allergy

Paracetamol is one of the most commonly used analgesic and antipyretic agents worldwide, attributed in part to its excellent safety profile when administered at recommended doses. Paracetamol allergy is not common, and the majority of the reactions are related to the pharmacological action of cyclooxygenase 1 inhibition. Selective and Immunoglobulin E (IgE)-mediated hypersensitivity reactions are rare. In this article, the authors report two cases of paracetamol allergy in which the mechanism of IgE-mediated hypersensitivity was demonstrated by positive skin tests and basophil activation tests. We highlight the relevance of identifying the mechanism underlying the reaction since patients with IgE-mediated paracetamol allergies will be able to tolerate non-steroidal anti-inflammatory drugs.

A review of published cases of Stevens-Johnson syndrome and toxic epidermal necrolysis associated with the use of acetaminophen

PURPOSE

Acetaminophen (paracetamol) is a widely used analgesic and antipyretic. In several studies, its use was associated with the occurrence of Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). This narrative review aimed to explore and summarise available cases of SJS/TEN suspected to be associated with acetaminophen reported in the literature.

MATERIALS AND METHODS

Electronic searches were conducted in PubMed/MEDLINE, Web of Science, Scopus and Serbian Citation Index (SCIndeks). Case reports or case series which reported detailed clinical description of the patients diagnosed with SJS, TEN or SJS/TEN overlap which was caused or suspected to be most likely caused by acetaminophen with available full text were included in the review.

RESULTS

Twenty-nine publications describing a total of 36 patients which satisfied inclusion criteria were included in the review. The age of the patients ranged from 3 to 77 years (median: 32.5 years). There were 15 female (41.7%) and 15 male (41.7%) patients, while for 6 patients (16.7%) gender was not reported. TEN, SJS and SJS/TEN overlap were diagnosed in 24 (66.7%), 10 (27.8%) and 2 (5.6%) patients, respectively. Reported time from the first dose of acetaminophen to the onset of the first symptoms of SJS/TEN ranged from promptly to 21 days, with a median of 3 days. Use of some form of supportive and symptomatic care was reported in 28 patients (77.8%). Systemic corticosteroids were reported to be administered in 25 patients (69.4%) and intravenous immunoglobulin in 16 patients (44.4%). All patients survived. Long-term consequences (sequelae) were reported in 5 patients (13.9%).

CONCLUSIONS

Clinicians should be aware that SJS/TEN may be an adverse effect of acetaminophen and keep in mind that its prompt recognition and withdrawal of the culprit drug along with supportive care is of utmost importance.

Acetaminophen-induced anaphylaxis: a case report

Acetaminophen is known to be generally safe, and the occurrence of anaphylaxis due to acetaminophen has been rarely reported. We report a case of acetaminophen-induced anaphylaxis in a healthy male subject who participated in a clinical trial on the pharmacokinetics of ibandronate. The subject had not experienced an allergic reaction to acetaminophen prior to this incident. The patient received 1300 mg oral acetaminophen at about 12 hours after receiving 150 mg ibandronate. After about 10 minutes, the subject developed whole-body urticaria and hypotension. The temporal association suggested that the anaphylaxis was due to acetaminophen and not ibandronate. Anaphylaxis could occur due to acetaminophen even in the absence of allergic reactions in the first dosing.

Paracetamol Allergy: A Case of a 9-Year-Old Female with a History of Atopy

Background: We describe a rare case involving paracetamol, a commonly used drug worldwide. Increased paracetamol consumption increases the risk of adverse drug reactions. Case Presentation: This is a case of a 9-year-old girl who visited the emergency department due to sudden onset sneezing, nasal itching, urticaria, and angioedema after paracetamol ingestion. The diagnostic and etiologic studies revealed an immunoglobulin E (IgE)-mediated hypersensitivity mechanism to paracetamol. Conclusion: Few cases of this phenomenon have been reported in previous literature. As confirmed in this study, a negative skin prick test did not exclude hypersensitivity, and conducting intradermal tests (IDTs) increased diagnostic accuracy. The patient had a positive IDT, confirming the underlying IgE-mediated reaction. The follow-up of a confirmed paracetamol hypersensitivity implies patient education about avoidance of any paracetamol-containing formulation, including combination products and clarification of available alternative drugs. This is likely the first publication documenting IgE-mediated paracetamol allergy in pediatric patients. We intend to underline the clinical benefits of diagnostic confirmation toward suspected drug hypersensitivity reactions in children, a particularly useful topic for pediatricians and pediatric allergists.

Behind the scene: Paracetamol hypersensitivity in children

BACKGROUND

Paracetamol, a non-steroidal anti-inflammatory drug, is commonly being used for fever and pain relief worldwide. The aim of this study was to evaluate children with a suspected history of paracetamol hypersensitivity.

METHODS

Sixty patients who were referred to our clinic in between January 2015 and December 2018 with a suspected history of paracetamol hypersensitivity were included. Reactions were classified according to the European Network for Drug Allergy (ENDA)/Global Allergy and Asthma European Network classification and European Academy of Allergy and Clinical Immunology (EAACI)/ENDA Position Paper. Diagnoses were confirmed by skin tests and oral challenge tests (OCTs). In those with verified paracetamol hypersensitivity, an OCT with a strong COX-1 inhibitor was performed to classify the type of the reaction to refer as either selective or cross-intolerance hypersensitivity. A subsequent OCT with a selective COX-2 inhibitor was performed in those cross-intolerant patients to find out a safe alternative drug.

RESULTS

Sixty OCTs with paracetamol were performed to patients with a median age of 8.5 years, and hypersensitivity to paracetamol was verified in 8 patients. Four children were classified as selective responders, and 3 were classified as cross-intolerant after OCT with a COX-1 inhibitor. Overall, skin test positivity for paracetamol was detected in only one patient, in whom OCT with paracetamol was negative. In all 3 cross-intolerant patients, a safe alternative non-steroidal anti-inflammatory drug was identified after an OCT with a selective COX-2 inhibitor.

CONCLUSION

OCT stands as the gold-standard procedure in verifying the diagnosis of patients with paracetamol-induced drug hypersensitivity, as well as, in defining the type of reactions and finding out safe alternative drugs.

Post-operative discomforts in children after extraction of primary teeth

Objectives

This prospective observational study aimed to evaluate discomfort after extraction of deciduous teeth under local anesthesia. The primary objective was to describe the prevalence of post‐extraction pain (PEP), post‐extraction bleeding (PEB), post‐extraction biting injury (PEBI), and analgesic usage in children. The secondary objective was to define whether it is possible to determine a profile of patients or a type of extraction procedure predictive to PEP, administration of analgesics, PEB, or PEBI.

Methods

One hundred and twenty‐five children, aged 3–13 years, with indications of at least one deciduous tooth extraction, were included. Immediately after extraction, information concerning the patient and the extraction were collected. Eighteen to 32 hr after extraction, parents were called by phone to request reports concerning the onset and intensity of PEP assessed using the Wong‐Baker Faces (WBF) scale, the administration of paracetamol (acetaminophen) to their children, and the appearance of PEB and/or PEBI.

Results

Of the children, 37.3% reported PEP (WBF ≥2), but 23.3% of these children did not receive any analgesic drugs to help relieve pain. Pain appeared before 3 hr after extraction in 69% of the children. Higher incidences of PEP and usage of analgesics were found both in the group of children with unfavorable socioeconomic level compared to favorable level and in the group with pre‐operative pain compared to no pre‐operative pain (p < .05).

Conclusions

About a third of the children reported pain after extraction, but the instructions for pain relief were not followed by all parents. The socioeconomic level of the young patient and the pain felt during the extraction were important predictors of discomfort. Therefore, our study could help the dentist to provide information on predicted post‐operative discomfort and to allow suitable care depending on the patient's profile or procedure.

Development and validation of a questionnaire on knowledge, attitude, and perception towards allergic reactions of paracetamol

Introduction:

National Pharmaceutical Regulatory Agency, Ministry of Health Malaysia has received 1018 adverse drug reaction reports related to paracetamol with 1972 adverse events from the year 2000 to February 2015. Serious skin reactions including Stevens–Johnson syndrome (SJS), toxic epidermal necrolysis, and acute generalized exanthematous pustulosis may develop as a result of allergic reactions of paracetamol. This study aimed to develop and validate a questionnaire regarding Knowledge, Attitude, and Perception towards Allergic Reactions of Paracetamol (KAP-ARP) among the general population.

Materials and Methods:

Content and face validity of the KAP-ARP were determined by four experts and 20 respondents, respectively. A questionnaire with 36 items, consisting of 16 Knowledge, 9 Attitude, and 11 Perception items, was distributed to 177 respondents. Exploratory factor analysis (EFA) was performed for construct validity. Cronbach’s alpha was used to determine the reliability of the questionnaire.

Results:

EFA constructed 13 Knowledge, 8 Attitude, and 8 Perception items. The final KAP-ARP questionnaire is reliable based on its internal consistency reliability (Knowledge: α = 0.78; Attitude: α = 0.63; Perception: α = 0.70).

Conclusion:

A valid and reliable questionnaire that is useful for measuring KAP-ARP among the general population has been developed.

Flare-Up Phenomenon of Intradermal Test with Anaphylactic Reaction to Paracetamol (Acetaminophen)

Background:

Paracetamol is a Non-Steroidal Anti-Inflammatory Drug (NSAID) that can produce hypersensitive reactions mediated by specific immunological mechanisms (IgE or T cell-dependent) or by a non-immunological mechanism (inhibition of cyclooxygenase COX-1).

Objective:

An 80-year-old man with a history of allergy to pyrazolones, with good tolerance to other NSAIDs was referred to our allergy department because he presented a generalized urticaria after the administration of Intravenous (IV) paracetamol.

Methods:

We performed an Intradermal Test (IDT) with paracetamol (0.02mg/ml) and later a Single Blind Oral Challenge Test (SBOCT) with oral paracetamol.

Results:

IDT reading at 15min showed negative result so an SBOCT was performed with oral paraceta-mol. With an accumulative dose of 250mg, after 20min, he developed discomfort, nausea and dizziness, urticarial, hypotension (BP 80/40) as well as flare-up phenomenon was observed in the site of the IDT with paracetamol. Tryptase levels during the reaction and 2hrs later were increased.

Conclusion:

We present an anaphylactic shock due to sensitization to paracetamol because of a type I hypersensitivity mechanism, diagnosed by SBOCT and a positive IDT because of flare-up phenomenon, in a patient with previous pyrazolones allergy and with tolerance to other NSAIDs. Some relevant patents are also summarized in this paper.

Spontaneous cutaneous adverse drug reaction reports-An analysis of a 10-year dataset in Singapore

We analyzed the spontaneous adverse event database in Singapore to determine the types of cutaneous adverse drug reactions (CADRs) and causative drugs reported. We selected 10 CADRs-of-interest, and identified the suspected drugs and the characteristics of the at-risk population. ADR reports received from 2006 to 2015 of the system organ class "Skin and Appendages Disorders" were analyzed based on patient demographics, the types of CADRs, suspected drugs, outcome, and latency period. Of the 104 372 reports analyzed, 56.2% involved females and 72.5% involved Chinese patients. The mean age was 41.1 years old. The top CADRs reported were rash (including nonspecified rash, follicular rash, maculopapular rash, and vesicular rash) (67.2%) and angioedema (13.9%). The drugs frequently associated with the CADRs-of-interest include nonsteroidal antiinflammatory drugs and antibiotics with angioedema, iohexol with urticaria, and antiepileptics and allopurinol with Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN). A subgroup analysis based on age, sex, and race on the 10 CADRs-of-interest showed the following trends in reporting: Alopecia (reported more in females), drug hypersensitivity syndrome (more in males), angioedema (more in younger patients), and photosensitivity (more in older patients). In general, the racial distribution across each CADR-of-interest was consistent with that of Singapore's population, with slight deviations observed for SJS/TEN, photosensitivity and skin discoloration. We analyzed CADR reports from Singapore over 10 years, and identified the types of CADRs reported, and their associated drugs, latency periods and patient characteristics. Such information could add value to healthcare professionals as they assess CADR cases and evaluate suspected drugs.

Hypersensitivity Reactions in Serious Adverse Events Reported for Paracetamol in the EudraVigilance Database, 2007⁻2018

Paracetamol is a popular and easily available drug which is used world-wide as analgesic, antipyretic agent. Hypersensitivity reactions to this drug involve a wide range of symptoms of various importance for patient management. The EudraVigilance (EV) database serves as a system for monitoring adverse events (AE) due to drug intake. We retrospectively recorded AE reports for "paracetamol" reported from 1 January 2007 to 1 October 2018 which fulfilled the category of "serious" in EV. For further analysis the retrieved AE reports were selected according to the keywords corresponding to hypersensitivity symptoms. We included in the study 4589 AE reports with 9489 particular AEs. 24.2% of all the AE reports concerned children. The most often reported symptoms were "angioedema," "rash" and "urticaria" (each of them with a frequency of >10% in the AE reports). An important group of AEs were oedema reported as being located in the head, neck or respiratory tract. We recorded 58 AE reports with fatal outcomes, including 9 Stevens-Johnson syndrome/toxic epidermal necrolysis cases (SJS/TEN), 10 anaphylactic reactions, 21 cases of hepatic failure and a further 18 cases which occurred for other reasons. SJS/TEN, acute generalized exanthematous pustulosis and drug reaction with eosinophilia and systemic symptoms were reported 129, 42 and 25 times, respectively. Prodromes and symptoms of potentially life-threating SJS/TEN appeared in 286 of the AE reports. 380 AE reports pointed to a diagnosis of anaphylaxis. To improve patient safety, healthcare professionals, including pharmacists, can identify warning signs of severe hypersensitivity reactions to paracetamol.

Diagnosing and managing patients with drug hypersensitivity

INTRODUCTION

Diagnosing and managing drug hypersensitivity is challenging because there are no clear limits between different types of drug reactions. Distinguishing between type A (predictable) and type B (hypersensitivity) reactions when a drug is introduced on the market is not easy. When many people use a drug, adverse reactions can occur, conditioned by diverse genetic profiles, viral infections or concomitant therapy. Occasionally the only tool clinicians have on which to base the diagnosis is the clinical history. Skins tests or in vitro tests sometimes have low sensitivity or are unavailable, and drug provocation tests may be dangerous or strictly forbidden in case of severe cutaneous reactions. Areas covered: This paper reviews the diagnosis and management of the two main types of immunological reactions: IgE-mediated immediate drug hypersensitivity reactions (IDHRs) and non-immediate drug hypersensitivity reactions (NIDHRs). Expert commentary: Although Europe and the United States use different diagnostic methods, patients with history of drug hypersensitivity must avoid the suspicious drug, and clinicians must assess tolerance to safe alternatives under medical surveillance. Sometimes desensitization may be required. There is a consensus about the need to perform genetic testing for specific drugs and give patients proper documentation to prevent future exposure to culprit drugs.

Discrepancies in the diagnosis and classification of nonsteroidal anti-inflammatory drug hypersensitivity reactions in children

BACKGROUND

Hypersensitivity to nonsteroidal anti-inflammatory drugs (NSAIDs) are frequently encountered in daily clinical practice. The aim of this study was to determine the confirmation rates, risk factors of NSAID hypersensitivity in children and to try to classify them with a standardized diagnostic protocol.

METHODS

All patients with a suspicion of NSAID-induced hypersensitivity were evaluated with European Network for drug Allergy (ENDA) recommendations. The children were classified as selective responders (SRs) or cross-intolerant (CI) depending on the drug provocation test (DPT) results.

RESULTS

We evaluated 106 children with a suspicion of NSAID hypersensitivity. NSAID hypersensitivity was confirmed with tests in 31 patients; 4 (12.9%) were diagnosed by skin tests and 27 (87.1%) by DPTs and two patients with a history of anaphylaxis by medical records. Eleven patients (33.3%) were classified as SRs, whereas twenty-two (66.6%) children as CIs. SRs and CIs were further classified as NSAID-induced urticaria/angioedema (n = 8), NSAID-exacerbated cutaneous disease (n = 6) and NSAID-exacerbated respiratory disease (n = 1) and single NSAID-induced urticaria/angioedema and/or anaphylaxis (n = 11). Eight (24.2%) patients could not be categorized according to ENDA/GA²LEN classification; one CI patient could not be classified based on pathomechanisms, seven CIs could not be categorized based on the underlying disease and clinical manifestations. A reaction within an hour of drug intake (aOR:3.0, 95% confidence interval: 1.18-7.67, p = 0.021), a history with multiple NSAIDs hypersensitivity (aOR:2.9, 95% confidence interval: 1.16-7.60, p = 0.022), and family history of atopy (aOR:4.0, 95% confidence interval: 1.50-10.82, p = 0.006) were found as the independent risk factors related to confirmed NSAID hypersensitivity.

CONCLUSIONS

This study suggests the presence of different phenotypes which do not fit into the current classifications in children with NSAID hypersensitivity.

Enigma: infection or allergy? Vancomycin-induced DRESS syndrome with dialysis-dependent renal failure and cardiac arrest

A man aged 73 years with infective endocarditis presented with septic shock and was started on immediate antimicrobial therapy. His blood culture yielded no organism. Subsequently, he developed a severe allergic reaction to prolonged empirical vancomycin therapy. This manifested as fever, widespread maculopapular rash and severe progressive acute kidney injury ultimately requiring dialysis. In the context of eosinophilia, this was determined to be drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome. Deciphering this complication as allergy in the context of severe infection required extreme caution due to the polarity of treatment with immunosuppression. Ultimately, this was used, with improvement of renal function, resolution of symptoms and absence of recurrence of infection. In summary, we present a case of vancomycin-related DRESS syndrome leading to dialysis-which is unique in the literature-complicating the treatment of culture-negative infective endocarditis.

Predictive value of a negative oral provocation test in patients with hypersensitivity to analgesics

INTRODUCTION

Nonsteroidal anti-inflammatory drugs (NSAIDs) take first or second place as the cause of drug-induced hypersensitivity reactions. The oral provocation test (OPT) is a gold standard for the diagnosis of NSAID hypersensitivity. We investigated which analgesics patients took after a negative OPT and determined the proportion of patients that experienced a hypersensitivity reaction despite a negative OPT.

METHODS

We selected 115 patients (67.8% female, age 54.9 ± 16.7 years) with a negative aspirin OPT and a convincing history of immediate hypersensitivity to aspirin or NSAIDs. In a telephone survey, we identified the analgesics taken after the OPT and possible adverse events.

RESULTS

The mean follow-up time was 5.1 ± 2.0 years. All subjects needed at least one analgesic drug. Despite the negative outcome of the aspirin OPT, only 33.9% of subjects took aspirin and 0.9% had a hypersensitivity reaction. The negative predictive value (NPV) of the aspirin OPT was 97.4%. Overall, 16 (13.9%) subjects experienced a hypersensitivity reaction, 12 of which occurred after taking a drug not tested with the OPT. The NPV of the OPT for all NSAIDs was 96.4%.

CONCLUSIONS

Our results support the available data that most subjects do not re-take the tested drug regardless of the high NPV of the OPT.

Biomonitoring of prenatal analgesic intake and correlation with infantile anti-aeroallergens IgE

An association between prenatal acetaminophen or ibuprofen intake and an increased risk of asthma and increased IgE level in children is discussed in various epidemiological studies. Although the molecular mechanistic link is still unknown, the question whether or not acetaminophen and/or ibuprofen are safe pain medications during pregnancy arose. In this study, we associate maternal acetaminophen and ibuprofen intake during pregnancy and breastfeeding to infantile asthma phenotypes and elevated IgE level. Therefore, we analysed questionnaires from a local mother-child cohort and monitored drug intake by LC-MS biomonitoring in urine. No association was found between drug intake and any analysed health outcome using questionnaire data. For the information obtained from biomonitoring, no association was found for ibuprofen and acetaminophen intakes during breastfeeding. However, an association between prenatal acetaminophen intake and increased infantile IgEs related to aeroallergens was statistically detected, but not for asthma phenotypes.

Seven steps to the diagnosis of NSAIDs hypersensitivity: how to apply a new classification in real practice?

Frequent use of non-steroidal anti-inflammatory drugs (NSAIDs) has been paralleled by increasing occurrence of adverse reactions, which vary from mild local skin rashes or gastric irritation to severe, generalized symptoms and even life-threatening anaphylaxis. NSAID-induced hypersensitivity reactions may involve both immunological and non-immunological mechanisms and should be differentiated from type A adverse reactions. Clinical diagnosis and effective management of a hypersensitive patient cannot be achieved without identifying the underlying mechanism. In this review, we discuss the current classification of NSAID-induced adverse reactions and propose a practical diagnostic algorithm that involves 7 steps leading to the determination of the type of NSAID-induced hypersensitivity and allows for proper patient management.

Anaphylaxis to Paracetamol in a Twelve-Year-Old Girl

Paracetamol (acetaminophen) is widely used and considered safe, since adverse reactions to this drug in therapeutic doses are rare, especially in children.^1,2 Only a few cases worldwide of anaphylaxis to paracetamol in children have previously been described.^2-11 Anaphylaxis is defined as a life-threatening reaction resulting from mast cell derived mediator release.¹² This report illustrates a case of anaphylaxis to oral paracetamol confirmed by an oral provocation test and an increase in serum tryptase level.

Drug allergies and implications for dental practice

Adverse reactions to medications prescribed or administered in dental practice can be worrying. Most of these reactions are somewhat predictable based on the pharmacodynamic properties of the drug. Others, such as allergic and pseudoallergic reactions, are generally unpredictable and unrelated to normal drug action. This article will review immune and nonimmune-mediated mechanisms that account for allergic and related reactions to the particular drug classes commonly used in dentistry. The appropriate management of these reactions will also be addressed.

Challenge-proven nonsteroidal anti-inflammatory drug hypersensitivity in children

BACKGROUND

Few studies investigated hypersensitivity to nonsteroidal anti-inflammatory drugs (NSAIDs) in children. The objective was to determine the frequency of true NSAID hypersensitivity (NSAID-H) and whether there were any parameters in the history of children that would predict NSAID-H. Secondly, an investigation was conducted into whether NSAID-hypersensitive children could tolerate safe alternatives. Differing from previous studies, the researchers followed the recent diagnostic algorithm proposed for acute reactions in NSAID-H.

METHODS

Children with a history suggesting NSAID-H were evaluated by an allergist. The patients with a single NSAID in history were tested first with a skin prick test and if negative challenged with the culprit NSAID. The patients who had reactions with multiple NSAIDs were directly challenged with their culprit drugs. Safe alternatives in children with a confirmed NSAID-H were found by oral provocation tests (OPTs).

RESULTS

Fifty-eight of 61 patients participated in the study. Thirty-eight patients (65.5%) described a reaction to a single NSAID and 20 mentioned reactions with ≥2 different NSAIDs. Single-drug-induced and cross-reactive NSAID-Hs were proven in 5 of 36 (14%) and 8 of 18 (44%) of patients, respectively. Acetaminophen and nimesulide were tolerated in 60% and 88.8% of the study patients as safe alternatives, respectively. Family history of NSAID-H was found as the only significant predictor of OPT (OR: 5.4; 95% CI: 1.02-28.6).

CONCLUSION

Histories of both single and multiple NSAID-Hs are poor predictors of actual drug hypersensitivity. Therefore, diagnostic tests should be performed in all children if no contraindication exits. Family history of NSAID-H is the only significant parameter predicting OPT results.

Classification and practical approach to the diagnosis and management of hypersensitivity to nonsteroidal anti-inflammatory drugs

Hypersensitivity reactions to aspirin (acetylsalicylic acid) and other nonsteroidal anti-inflammatory drugs (NSAIDs) constitute only a subset of all adverse reactions to these drugs, but due to their severity pose a significant burden to patients and are a challenge to the allergist. In susceptible individuals, NSAIDs induce a wide spectrum of hypersensitivity reactions with various timing, organ manifestations, and severity, involving either immunological (allergic) or nonimmunological mechanisms. Proper classification of reactions based on clinical manifestations and suspected mechanism is a prerequisite for the implementation of rational diagnostic procedures and adequate patient management. This document, prepared by a panel of experts from the European Academy of Allergy and Clinical Immunology Task Force on NSAIDs Hypersensitivity, aims at reviewing the current knowledge in the field and proposes uniform definitions and clinically useful classification of hypersensitivity reactions to NSAIDs. The document proposes also practical algorithms for the diagnosis of specific types of NSAIDs hypersensitivity (which include drug provocations, skin testing and in vitro testing) and provides, when data are available, evidence-based recommendations for the management of hypersensitive patients, including drug avoidance and drug desensitization.

World Allergy Organization Anaphylaxis Guidelines: 2013 update of the evidence base

The World Allergy Organization (WAO) Guidelines for the assessment and management of anaphylaxis are a widely disseminated and used resource for information about anaphylaxis. They focus on patients at risk, triggers, clinical diagnosis, treatment in health care settings, self-treatment in the community, and prevention of recurrences. Their unique strengths include a global perspective informed by prior research on the global availability of essentials for anaphylaxis assessment and management and a global agenda for anaphylaxis research. Additionally, detailed colored illustrations are linked to key concepts in the text [Simons et al.: J Allergy Clin Immunol 2011;127:593.e1-e22]. The recommendations in the original WAO Anaphylaxis Guidelines for management of anaphylaxis in health care settings and community settings were based on evidence published in peer-reviewed, indexed medical journals to the end of 2010. These recommendations remain unchanged and clinically relevant. An update of the evidence base was published in 2012 [Simons et al.: Curr Opin Allergy Clin Immunol 2012;12:389-399]. In 2012 and early 2013, major advances were reported in the following areas: further characterization of patient phenotypes; development of in vitro tests (for some allergens) that help distinguish clinical risk of anaphylaxis from asymptomatic sensitization; epinephrine (adrenaline) research, including studies of a new epinephrine auto-injector for use in community settings, and randomized controlled trials of immunotherapy to prevent food-induced anaphylaxis. Despite these advances, the need for additional prospective studies, including randomized controlled trials of interventions in anaphylaxis is increasingly apparent. This 2013 Update highlights publications from 2012 and 2013 that further contribute to the evidence base for the recommendations made in the original WAO Anaphylaxis Guidelines. Ideally, it should be used in conjunction with these Guidelines and with the 2012 Guidelines Update.

Severe drug-induced anaphylaxis: analysis of 333 cases recorded by the Allergy Vigilance Network from 2002 to 2010

BACKGROUND

A few series of well-documented cases of severe drug-induced anaphylaxis (SDA) are available.

METHODS

Cases collected by the Allergy Vigilance Network from 2002 to 2010 were analyzed for clinical signs, causative drugs, and efficacy of a stepwise approach to diagnosis, using skin tests, laboratory tests, and oral challenges.

RESULTS

Three hundred and thirty-three cases concerned 300 adults (90.1%) and 33 children (9.9%): 206 females (61.9%) and 127 males (38.1%). Mean age was 42.7 ± 18 years. Anaphylactic shock (76.6%), severe systemic reactions (10.5%), acute laryngeal edema (9%), severe bronchospasm (2.1%), and six fatal cases (1.8%) were recorded. There were 270 cases (81.1%) of ambulatory anaphylaxis. Sixty-three cases (18.9%) occurred during anesthesia. Hospitalization was required in 94.8% of cases. 23.7% of patients were admitted to an intensive care unit. Epinephrine was used in 57.9% of cases. Eighty-four drugs were incriminated: antibiotics (49.6%), muscle relaxants, latex and anesthetics (15%), nonsteroidal anti-inflammatory drugs (10.2%), acetaminophen (3.9%), iodinated or magnetic resonance imaging contrast media (4.2%), immunotherapy and vaccines (3.9%), and other drugs (13%). Among antibiotics, amoxicillin (97 cases), other penicillins (four cases), cephalosporins (41 cases), quinolones (15 cases), and pristinamycin (seven cases) were the most common. The diagnosis of drug hypersensitivity was obtained by skin tests in 72.9%, laboratory tests only in 2.4% of cases, and oral challenges (OCs) only in 3.9% of cases.

CONCLUSIONS

Three hundred and thirty-three case reports provided data on drugs involved in severe anaphylaxis. The efficacy of skin tests and poor use of laboratory tests are underlined. Further progress may depend on OCs.