Drug allergy

Characterization of Potential Intoxications with Medicines in a Regional Setting

The Portuguese Poison Information Center (from Portuguese—CIAV) is a call center that offers medical assistance in case of possible intoxication with any kind of product, including medicines. This center´s main goal is to inform and guide the general public and health professionals. This work aimed to analyze and compare data corresponding to the telephone calls from the Algarve region (South of Portugal), received by CIAV during 2019 and 2020, regarding potential intoxications with medicines. To this end, data provided by CIAV on possible cases of medication intoxication in the Algarve region were collected, including the number of calls received, the place of origin of the call, the age group and sex of the intoxicated individual, the route of exposure to the drug, the circumstances of contact with the substance, the existence of symptoms, and the drug or drugs involved in the potential intoxication. The results showed that the number of cases slightly decreased in 2020 (n = 1261) compared with 2019 (n = 1340), with a high number of cases of intoxication in children between one and four years old in both years (21.2%; n = 152 in 2019; 16.4%; n = 115 in 2020). The drugs belonging to the locomotor system group (paracetamol and ibuprofen) were the main drugs involved, followed by the central nervous system pharmacotherapeutic group, namely benzodiazepines (diazepam and alprazolam). Paracetamol was the main drug responsible for the calls to CIAV (n = 71 in 2019; n = 63 in 2020), while for the remaining drugs there were fluctuations in their positions between both years. In some cases, this swinging may be explained by the possible changes in therapy due to potential interactions with drugs used for the treatment of symptoms of COVID-19 or perhaps related to misleading information released by the media about the use of some drugs, such as ibuprofen, during lockdown periods. Although there has been a decrease in calls to report possible drug intoxication in the Algarve region, the profile of calls was very similar. Paracetamol was the drug with the highest number of reported cases and the group of psychotropic drugs showed the largest increase between 2019 and 2020.

Renal Hypersensitivity Vasculitis Associated With Dapsone

We describe clinical and pathological features of kidney and skin involvement in a patient with hypersensitivity vasculitis associated with dapsone. Although visceral damage occurs rarely, similar skin and kidney histopathologic and immunohistochemical findings indicate that this organ is a target for type IV cell-mediated dapsone reaction. To our knowledge, this is the first reported case of renal hypersensitivity vasculitis associated with dapsone.

A review of evidence supporting the American Academy of Pediatrics recommendation for prescribing cephalosporin antibiotics for penicillin-allergic patients

The American Academy of Pediatrics, evidence-based guidelines endorse the use of cephalosporin antibiotics for patients with reported allergies to penicillin, for the treatment of acute bacterial sinusitis and acute otitis media. Many physicians, however, remain reluctant to prescribe such agents. Although such concern is understandable, lack of consistent data regarding exactly what constitutes an initial penicillin-allergic reaction and subsequent cross-sensitivity to cephalosporins may be preventing many patients from receiving optimal antibiotic therapy. This article reviews evidence in support of the American Academy of Pediatrics recommendation. Included is an examination of the types and incidence of reactions to penicillins and cephalosporins; the frequency of cross-reactivity between these 2 groups of agents; experimental and clinical studies that suggest that side chain-specific antibodies predominate in the immune response to cephalosporins, thereby explaining the lack of cross-sensitivity between most cephalosporins and penicillins; the role of skin testing; and the risks of anaphylaxis. Specific recommendations for the treatment of patients on the basis of their responses to previously prescribed agents are summarized.

Hypersensitivity vasculitis induced by cefoperazone/sulbactam

BACKGROUND

Cefoperazone has not been reported to cause vasculitic complications before. Here, we report a case of hypersensitivity vasculitis associated with cefoperazone/sulbactam.

CASE PRESENTATION

A 13-year-old girl with appendicitis developed hypersensitivity vasculitis on the fifth day of cefoperazone/sulbactam therapy. Hypersensitivity vasculitis resolved gradually after removal of the agent on the seventh day and did not recur. Although hypersensitivity vasculitis has multiple causes, coexistence of hypersensitivity vasculitis and cefoperazone treatment, and the quite resolution of the disease after removal of the drug, strongly favours a causative relationship.

CONCLUSION

To our knowledge, this is the first report of a hypersensitivity vasculitis associated with cefoperazone.

Adverse drug reactions in patients with gastroenterological diseases: does age increase the risk?

BACKGROUND

It has been claimed that the risk of adverse drug reactions increases with age. However, only limited data exist for disease-group specific risks and none for patients with liver and gastrointestinal diseases.

AIMS

To determine the incidence and characteristics of adverse drug reactions and the physicians' awareness of adverse drug reactions.

METHODS

During a 7-month period, a prospective survey of 532 male patients (158 aged 65 years or older; 30%) was conducted on a hepatogastroenterological ward of a tertiary-care university hospital, using intensive bedside and computer-assisted drug surveillance methods.

RESULTS

No difference was found in the overall rate of adverse drug reactions between older and younger patients (25.9% vs. 24.2%) during 6213 treatment days. However, a significantly higher risk for developing adverse drug reactions could be shown for the elderly with biliary tract diseases (P < 0.01). Independently of age, patients suffering from gastric ulcers, acute episodes of pancreatitis, cholangitis or inflammatory bowel diseases were at high risk of adverse drug reactions. Adverse drug reaction-associated mortality was encountered in four elderly and none of the younger patients. Secondary pharmacological effects and drug toxicity were the main types of adverse drug reactions for both age groups. Although 75.3% of the adverse drug reactions were predictable, only 37.5% of all adverse drug reactions were recognized by the staff physicians.

CONCLUSION

In hepatogastroenterological patients, advancing age was not associated with an overall increased risk of adverse drug reactions except for patients with biliary tract diseases. In the elderly, adverse drug reactions were more severe and carried higher mortality. Guidelines and educational programs should be developed to increase the awareness of adverse drug reactions and their prevention, especially in high risk patients and, thus, to improve patient outcomes.

Allergy to beta-lactam antibiotics in children

BACKGROUND

Skin tests with soluble beta-lactams can be used to diagnose immediate and delayed hypersensitivity (HS) reactions to beta-lactam antibiotics. Very few studies have been performed with children with suspected beta-lactam allergy. In these studies, immediate HS to beta-lactams was diagnosed by skin tests in 4.9% to 40% of children. The diagnostic and predictive values of immediate responses in skin tests are good, because very few children with negative skin test results have positive oral challenge (OC) test results. Delayed responses in skin tests (intradermal and patch tests) have been reported in adult patients and children suffering with urticaria, angioedema, and maculopapular rashes during treatments with beta-lactam antibiotics. However, the diagnostic and predictive values of late responses are unknown. Semi-late responses in skin tests with beta-lactams have never been studied in adults or children.

OBJECTIVES

The aims of this study were to confirm or rule out the diagnosis of allergy to beta-lactams in children with histories of adverse reactions to these antibiotics, to determine whether allergic children were sensitized to one or several classes of beta-lactams, and to evaluate the frequency and diagnostic value of immediate, accelerated, and delayed responses in skin tests with beta-lactam antibiotics in children.

METHODS

We studied 325 children with suspected beta-lactam allergy. Skin tests (prick and intradermal) were performed with soluble forms of the suspected (or very similar) beta-lactams and with one or several beta-lactams from other classes. The reaction was assessed after 20 minutes (immediate), 8 hours (accelerated), and 48 to 72 hours (delayed). OCs with the suspected beta-lactams were performed in patients with negative skin test results, except those with severe serum sickness-like reactions and potentially harmful toxidermias.

RESULTS

Skin tests and OCs led to the diagnosis of beta-lactam allergy in 24 (7.4%) and 15 (4.6%) of the children, respectively. Thus, only 12% of the children were diagnosed as allergic to beta-lactams by means of skin tests and OC. HS to beta-lactams was suspected from clinical history in 30 (9.2%) children reporting serum sickness-like reactions and potentially harmful toxidermias. In a few children, we diagnosed food allergy and intolerance to excipients or nonsteroidal antiinflammatory drugs. No cause was found in the other children. Based on skin tests and OC, the prevalences of immunoglobulin E-dependent and of semi-late or delayed sensitizations to beta-lactam assessed were similar (6.8% vs 5.2%, respectively). Most immunoglobulin E-dependent sensitizations were diagnosed by means of skin tests (86.4%). In contrast, most semi-late and delayed sensitizations were diagnosed by OC (70.6%). The likelihood of beta-lactam allergy was significantly higher for anaphylaxis (42.9% vs 8.3% in other reactions) and immediate reactions (25% vs 10% in accelerated and delayed reactions). Of the children diagnosed as allergic to beta-lactam by means of skin tests, OC, and clinical history, 11.7% were sensitized to several classes of beta-lactams. The risk was significantly higher in children with anaphylaxis (26. 7% vs 7.5% of the children with other reactions) and in children reporting immediate reactions (33.3% vs 8.5% of the children with accelerated and delayed reactions). Finally, age, sex, personal history of atopy, number of reactions to beta-lactams, and number of reactions to other drugs were not significant risk factors for beta-lactam allergy.

CONCLUSION

The skin tests were safe, and the immediate reaction to skin tests successfully diagnosed allergy to beta-lactam antibiotics in children reporting reactions suggestive of immediate HS. In contrast, most accelerated and delayed reactions were diagnosed by OC. Thus, our results suggest that the diagnostic and predictive values of skin tests for nonimmediate HS to beta-lactams in children are low. (ABSTRACT TRU

[Exploration of 112 children suspected of amoxicillin allergy. Indications and efficacy of oral provocation test]

BACKGROUND

One to 10% of treatments using betalactams, particularly synthetic penicillin, are complicated by allergic reactions, usually cutaneous, and not easily imputable to immunologic sensitization in children.

PATIENTS AND METHODS

The aim of this study was to identify, using cutaneous and biological tests, those from a group of 112 children suspected of amoxicillin allergy (evidenced by rash) who were actually sensitized, and to confirm the absence of allergy in others by an oral provocation test (OPT) associated to a long-term survey. The cutaneous tests were made by prick test and intra-dermo reaction (IDR) with Allergopen and with amoxicillin or amoxicillin + clavulanic acid. The biological tests included examination for penicillin and amoxicillin antibodies by using various techniques including enzyme-linked immunosorbent assay (ELISA) immunoglobulin G (IgG) and IgE, FARR, radioallergo sorbent test (RAST) and a histaminoliberation. When these tests were negative, an OPT with the suspected antibiotic was subsequently performed.

RESULTS

Thirty-nine children (36.4%) confidently presented at least one positive cutaneous test (38 Allergopen, ten amoxicillin); 25 biological tests were positive (16 ELISA IgE, one ELISA IgG and eight histaminolibarations), seven times with negative cutaneous test. Forty-five children were judged to be sensitized to amoxicillin, with only one who subsequently took amoxicillin again. Among the 67 others, 52 received an OPT, six of them with moderate cutaneous reactions. Fifty-one (45.5%) children were allergic and 46 (41%) were allowed to take amoxicillin again; 17 did, one of them with a benign cutaneous reaction.

CONCLUSION

Efficacy and safety of this type of investigation seems clear; it will have to be confirmed by other studies.

In vivo and in vitro testing for adverse drug reactions

The goal of providing an accurate and reliable diagnostic test for the evaluation of adverse drug reactions remains elusive. Rechallenge remains a truly conclusive method for determining the contribution of drugs to adverse effects, but there are significant disadvantages in exposing patients to drugs that may have caused serious adverse effects. Skin tests are useful for the assessment and predictive risk of serious adverse reactions for a small number of drugs, but skin tests are limited in their utility to adverse drug reactions mediated by Type 1 hypersensitivity. Skin tests must be performed with care and rigor as well. There are a number of in vitro assays that have been used for the assessment of adverse drug reactions, but many of these assays are primarily research tools and have little utility in the clinical setting. Although in vitro tests are not yet readily available for the diagnosis of adverse drug reactions, our increasing understanding of the biology of adverse drug reactions and interactions between the immune system and xenobiotics offers promise that more clinically relevant assays can be developed. At the present time, the primary diagnostic tools for the assessment of adverse drug reactions remain a careful history and physical examination and an astute, insightful physician.

Mechanisms of unpredictable adverse drug reactions

Adverse drug reactions are common problems associated with therapy, and are major sources of morbidity and mortality. There are numerous types of drug reactions, including predictable drug reactions such as side effects, toxicity, drug interactions and secondary effects that can be anticipated when planning therapy. There are also a number of unpredicted adverse effects, which are unexpected consequences of therapy. The least severe unpredicted adverse drug reaction is intolerance, which appears to be an exaggeration of pharmacological or toxic effects of the drug among vulnerable subsets of patients. Some of the most severe and life-threatening adverse drug reactions are allergic. These adverse effects can be mediated by a number of mechanisms, including the development of drug-specific IgE, serum-sickness-like reactions in response to drug-antibody complexes, direct release of inflammatory mediators, or involvement of the immune system by mechanisms that are poorly understood. Idiosyncratic adverse drug reactions are a heterogeneous group of adverse effects that are not predictable from the pharmacological actions of the drug. Many of these reactions occur as a consequence of pharmacogenetic variations in drug bioactivation and drug or metabolite detoxification or clearance. The physician must be vigilant for the possibility of unpredictable adverse drug reactions during or after therapy. Research currently underway may afford the opportunity to predict, and hopefully prevent, some of these adverse reactions in the future.

The lymphocyte transformation test with sulphadiminidum and with prealbumin-sulphadiminidum complex in patients with drug allergy

Earlier results (the absence or a decreased level of prealbumin [PA] in the serum, a higher proportion of PA-bearing lymphocytes as antigen-binding cells, and the presence of PA in the eluate of lymphocytes in patients with drug allergy) permitted the conclusion that, besides its other relevant functions, PA may also behave as a hapten carrier protein. The lymphocyte transformation test (LTT) involving measurement of 3H-thymidine uptake was therefore carried out with sulphadiminidum (SA) alone, with the PA-SA complex, and with the albumin-SA complex in patients with proven (3 cases) or suspected (63 cases) sensitivity to SA. In all 3 cases with proven drug allergy to SA and in 5 of the 63 suspect cases, the LTT was positive in response to both the drug alone and to the PA-SA complex (The albumin-SA complex gave positivity in only one case). In 5 of the 63 suspect cases, the LTT was positive only in response to the PA-SA complex. It is suggested that the sensitivity of the LTT could be increased if the test could be run with a complex of a protein (hapten carrier?) and a drug.

Immunopharmacology and adverse drug reactions

Adverse drug reactions are common and troublesome complications of contemporary pharmacotherapy. Adverse drug reactions are frequently, and often incorrectly, referred to as "allergy". Although there are multiple mechanisms for adverse drug reactions, adverse drug reactions mediated by the immune system account for a disproportionate number of fatal and serious adverse reactions, and constitute a major clinical problem for patients and physicians. The immune system has evolved in multicellular organisms as a defence against infection. Interactions between drugs and the immune system occur as inadvertent consequences of the protective function of the immune system, with drug molecules or drug-carrier haptens being recognized as "non-self" by the immune system. The classical mechanisms for drug hypersensitivity described by Gell and Coombs (Types 1 to 4) include IgE-mediated, cytotoxic, immune complex-mediated and delayed mechanism. These mechanisms provide elegant models for drug-immune interactions that can provide mechanistic explanations for events such as urticaria associated with penicillins. However, these mechanisms do not account for many of the immunologically mediated adverse reactions commonly encountered in clinical practice. Over the last two decades, there has been an increasing awareness of the importance of reactive drug metabolites and drug-protein interactions in the initiation of immunologic events mediating adverse drug reactions. Reactive drug metabolites may produce direct and profound effects on various functions of the immune system. Although some adverse reactions mediated by the immune system occur with equal frequency among adults and children, some of these reactions appear to be markedly more common among children than adults.(ABSTRACT TRUNCATED AT 250 WORDS)

Profound specific suppression by antigen of persistent IgM, IgG, and IgE antibody production

Ongoing, high-titer T-cell-dependent immune responses in adult mice, consisting of IgM, IgG, and IgE anti-fluorescein antibodies, can be specifically and substantially reduced (90-99%) when the mice are injected with appropriate doses of fluoresceinated dextran of defined molecular weight and hapten valence. This suppressive form of the antigen is nontoxic and specific, as responses to other antigens are unaffected. The suppression is long lasting and reduces high-affinity antibodies most markedly. Moreover, plasma cell secretion of specific antibody is virtually eliminated. This demonstrates that the reduction in antibody titer is not simply due to masking of serum antibody by the suppressive polymer. The results are discussed with reference to proposed models of B-cell and T-cell tolerance. Extension of these findings to disease-related immunogens may yield effective antigen-specific treatments of human allergy and autoimmune diseases.

Drug allergy. Best diagnostic and treatment approaches

The problems in identifying and managing drug allergy are myriad, primarily because of the number of possible agents involved, the lack of objective diagnostic methods, and the varied signs and symptoms that may occur. Allergic reactions can be life-threatening and are avoidable in most cases. A careful and serious approach is important because the effect of medical decisions can be significant. Physicians should keep in mind that an allergic reaction to any drug can occur in any patient at any time.

Proving penicillin allergy

Allergic reactions to penicillin are usually short-lived and reversible, but they can be fatal. What causes these reactions? Can they be avoided? How is the risk of penicillin allergy evaluated? Drs Erffmeyer and Blaiss describe the full spectrum of allergic, immune, and nonimmune reactions to penicillin and discuss how to assess and treat patients with suspected penicillin allergy.