Educational case series: Mechanisms of drug allergy

Recurrent injection site reactions to vaccines: Two clinical patterns of presentation

After administration of injectable vaccines, skin manifestations are common and they usually disappear in a few hours or days. We describe a case series of recurrent injection site reactions in 8 children undergoing vaccines of the regional immunization schedule, which required specialized evaluation and advice for subsequent vaccinations. Two clinical patterns of reactions were observed. Four children manifested recurrent wheal and erythema with pruritus at vaccine injection site for up to 7 months; the remaining children showed an itching plaque or nodule at injection site, that lasted several months after vaccination with exacerbations of pruritus and erythema. Hypersensitivity to aluminium salts was demonstrated in the second group. The flare-up manifestations, related to Meningococcal B vaccine in 5 reactions, were triggered by concurrent viral infections in two patients. Communication of risks and diagnostic testing, when appropriate, resulted important to reassure parents of children and favour adequate completion of vaccination.

Serum soluble Fas ligand levels and peripheral blood lymphocyte subsets in patients with drug-induced maculopapular rashes, dress, and viral exanthemas

BACKGROUND

Fatty acid synthetase (Fas)/Fas ligand (FasL)-dependent apoptotic pathways have been reported as being involved in the pathogenesis of drug-induced maculopapular rashes.

OBJECTIVE

We investigated serum soluble FasL (sFasL) levels and peripheral blood lymphocyte subtypes to discriminate maculopapular drug eruptions (MPDE) from viral exanthema (VE).

PATIENTS/METHODS

Children with confirmed MPDE (group I), VE (group II), and drug rashes with eosinophilia and systemic symptoms (DRESS) or drug-induced hypersensitivity syndrome (DIHS) (group III) were included. Serum sFasL levels and peripheral blood lymphocyte subtypes were analyzed in groups I-III on admission, and repeated twice (only once for group IV - controls).

RESULTS

There were no significant serum soluble FasL level differences among the groups for all the samples. In the initial samples, CD19⁺ cell numbers in group II were significantly higher than in group IV, and the CD4⁺/CD8⁺ ratio was higher than groups I and IV. In the second samples, CD4⁺ and CD19⁺ cell numbers were significantly higher in group II than group I. In the final samples, CD4⁺ cell numbers in group II were significantly higher than group I and group III. CD19⁺ cells numbers in group III were significantly lower than the other groups for all samples.

CONCLUSION

Serum sFasL levels were not found to be useful in discriminating viral exanthemas from other drug rashes. The significant differences between MPDE, VE, and DRESS were high CD4⁺ and CD19⁺ cell-count numbers in VE but low B-cell numbers in DRESS. This might be important for discriminating VE from DRESS, and the low B-cell count in early symptoms might be a useful predictor of DRESS development.

Short and extended provocation tests have similar negative predictive value in non-immediate hypersensitivity to beta-lactams in children

INTRODUCTION AND OBJECTIVES

Drug provocation tests (DPTs) are the gold-standard method to diagnose non-immediate hypersensitivity reactions (NIHSR) to beta-lactam antibiotics (BL) in children. Our aim was to compare the negative predictive value (NPV) of one-day (short) DPT versus 3-7 days (extended) DPT for the diagnosis of NIHSR to BL in paediatric age. A secondary aim was to compare confidence on drug re-exposure after short and extended negative DPTs.

METHODS

The occurrence of HSR on drug re-exposure and drug refusal after negative diagnostic DPTs were evaluated in children/adolescents with a history of NIHSR to BL using a questionnaire performed six months to ten years after DPT. Patients were divided into two groups according to the protocol performed: short DPT vs. extended DPT.

RESULTS

We enrolled 212 children and adolescents (86 females, 126 males, mean age at DPT 5.52 years, p25=3 years, p75=7.25 years): 69 tested with short DPT, and 143 with extended DPT. The NPV of both types of DPT together was 95.2%. The NPV of short DPT was 97.5% and the NPV of extended DPT was 93.8% (p=0.419). After negative DPT, beta-lactams were refused by carers in 14.75% of the children requiring subsequent treatment, 6.98% in the short DPT group and 18.99% in the extended DPT group (p=0.074).

CONCLUSIONS

In our paediatric sample, prolonging drug administration did not increase the NPV of diagnostic DPT for NIHSR to BL or reduce drug refusal. Altogether, the data here reported suggest that, however intuitive, prolonging DPT is not beneficial in the parameters analysed.

Impact of an extended challenge on the effectiveness of β-lactam hypersensitivity investigation

BACKGROUND

Drug provocation tests (DPTs) are the gold standard in the diagnosis of β-lactam hypersensitivity. However, no consensus exists on the need for extended provocation tests, even though the effectiveness of the short DPT is relatively low and there has been an increase in the relative incidence of nonimmediate hypersensitivity reactions.

OBJECTIVE

To evaluate the effectiveness of a 7-day (extended) DPT compared with a 1-day-only (short) DPT in the management of hypersensitivity reactions to β-lactam antibiotics.

METHODS

Patients referred to the allergy clinic of the Sheba Medical Center for suspected β-lactam hypersensitivity from January 2008 to December 2012 underwent in vivo skin tests and an immediate short DPT with the culprit drug. Unless an immediate reaction was clearly documented, patients were offered a 7-day, extended DPT. Long-term effectiveness, calculated as the subsequent use of the tested antibiotic, and satisfaction levels were assessed with a telephone questionnaire.

RESULTS

Of 49 negative DPT results, 26 (53%) were long and 23 (47%) were short. A total of 78% of the patients who underwent the long DPT reported that they used the drug compared with 61% of those who underwent only the short DPT (P = .049). Most patients were very satisfied with the drug allergy evaluation process.

CONCLUSIONS

An extended DPT protocol increased the effectiveness of the allergy workup in our center without compromising patient satisfaction and safety, and it should be recommended to patients with a history of nonimmediate reaction to β-lactam.

Lamotrigine induced DIHS/DRESS: Manifestations, treatment, and outcome in 57 patients

OBJECTIVE

To evaluate the clinical features, course, response to treatment, and outcome of lamotrigine induced drug-induced hypersensitivity syndrome (DIHS) or drug reaction with eosinophilia and systemic symptoms (DRESS).

METHODS

A comprehensive PubMed and Scopus search (covering the period from January 1999 through April 2014) of the English and non-English literature (with English abstract) was conducted to identify published reports of severe cutaneous adverse reactions (SCARs) associated with lamotrigine therapy.

RESULTS

This study population included 57 patients, of whom 38 (66.67%) were female and 19 (33.33%) were male. The latency period varied from 9 days to 120 days, with a mean of 27.58 ± 20.65 days. Multisystem involvement was present in 97.37% (37/38) patients. Systemic corticosteroids were administered to (61.29%) 19/31 patients. 35/38 (92.11%) patients recovered completely, one patient developed liver failure and needed liver transplant, one died from septic shock and one died from multiple organ failure.

CONCLUSIONS

We found a greater predominance of women with LTG-DIHS/DRESS, and 68.42% patients were >18 years of age. The presenting symptoms in most of patients were fever, skin rash, liver involvement, hypereosinophilia, and lymphadenopathy. Lamotrigine is associated to a rather high risk of severe cutaneous adverse reactions and to the risk of dying from such reactions, likes many other anticonvulsants. Early recognition and withdrawal of the suspected agent may avoid irreversible damage to the organs will be life saving.

The diagnosis and management of antibiotic allergy in children: Systematic review to inform a contemporary approach

BACKGROUND

Adverse drug reactions (ADRs) to antibiotics are commonly reported among children, with some representing genuine drug allergies. Accurate diagnostic tests are required. Drug provocation testing (DPT) is accepted as the gold standard investigation among children with suspected antibiotic allergy. We conducted this review to ascertain the strength of current evidence for using DPT as the first-line investigation for suspected antibiotic allergy among children.

METHODS

Medline was searched in June 2014 for publications investigating antibiotic allergy among children.

RESULTS

865 publications were retrieved and 76 studies selected. ADRs are most common among children of 0-4 years, however only some reveal drug allergies. The best evidence demonstrates that around 0.21% of general paediatric outpatients demonstrate positive antibiotic intradermal (ID) testing or DPTs, while 6.8% of children attending emergency departments for suspected β-lactam allergy may fulfil DPT reactions. Four studies used DPT-based protocols to investigate suspected antibiotic allergy, with two of these conducting ID testing and DPTs across all participants. β-lactam and clarithromycin ID testing had sensitivities of 66.7% and 75%, with positive predictive values of 36% and 33%, respectively, when compared with DPT data.

CONCLUSIONS

Our literature review found four (6%) publications that performed DPTs to subjects' index antibiotic across all participants. No rigorous evidence supports using skin prick, ID or in vitro diagnostic testing; indeed, the testing regimens, extracts and positivity criteria used are inconsistent. We recommend that suspected non-serious antibiotic allergy should be primarily investigated using DPT-based clinical protocols. Data examining their safety, acceptability and diagnostic performance are required.

T-cell receptor and carbamazepine-induced Stevens-Johnson syndrome and toxic epidermal necrolysis: understanding a hypersensitivity reaction

Ample evidence exists to support the view that drug hypersensitivity is mediated by adaptive immunity, which involves MHC-restricted drug presentation, activation and clonal expansion of T cells. The specific MHC molecules implicated in hypersensitivity have been identified; for example, HLA-B*5701 in abacavir-induced drug hypersensitivity and HLA-B*1502 in carbamazepine-induced Stevens-Johnson syndrome. However, little is known about the role of drug-specific T cells and their T-cell receptors (TCRs) in the pathogenesis of drug hypersensitivity. Using the combination of a strong HLA-B*1502 predisposition in carbamazepine-induced Stevens-Johnson syndrome and applying global analysis of the TCR repertoire, restricted and common TCR usage in the development of severe drug hypersensitivity have recently been documented. This article reviews recent advances in the understanding of the pathogenic role of drug-specific T cells and their TCRs in the development of drug hypersensitivity and provides an analysis of their potential clinical implications.

Diagnosing multiple drug hypersensitivity in children

BACKGROUND

Multiple drug hypersensitivity (MDH) has been defined as a hypersensitivity to two or more chemically different drugs. Two types of MDH have been reported: the first one, which develops to different drugs administered simultaneously and the second type, in which sensitizations develop sequentially. In children, studies which diagnose MDH on the basis of positive allergologic tests to 2 or more chemically different drugs are lacking.

METHODS

We conducted a prospective study evaluating children with histories of MDH by skin tests, patch tests, serum-specific IgE assays, and drug provocation tests.

RESULTS

A MDH was diagnosed in 7 (2.5%) of the 279 children evaluated who completed the study. The responsible drugs were β-lactams (penicillins and cephalosporins) in 5 episodes, ibuprofen and anticonvulsants in 3, and erythromycin, fentanyl, methylprednisolone, and cotrimoxazole in 1. Sensitivity to 2 chemically different drugs was diagnosed in 6 children and to 3 drugs in 1 child. Two of the 7 children presented the first type of MDH, whereas 5 displayed the second one.

CONCLUSIONS

MDH can occur in children, even to drugs other than antibiotics. It is crucial to evaluate children with histories of MDH using both in vivo and in vitro allergologic tests, including challenges. In fact, such approach allows the physician to confirm the diagnosis of MDH in a small percentage of children with histories of MDH, as well as to rule it out in the great majority of them.

Hypersensitivity reactions to proton pump inhibitors

PURPOSE OF REVIEW

Proton pump inhibitors (PPI) are one of most frequently prescribed drugs in the world. The purpose of this review is to describe the hypersensitivity reactions to PPI.

RECENT FINDINGS

Hypersensitivity reactions to PPI vary from mild symptoms to life-threatening disorders. Cases of urticaria, angioedema, anaphylaxis, cytopenia, vasculitis, acute allergic interstitial nephritis, occupational contact dermatitis, photoallergic dermatitis, maculopapular eruption, erythroderma, Drug rash with eosinophilia and systemic symptoms (DRESS) syndrome, Stevens-Johnson syndrome/toxic epidermal necrolysis, and other autoimmune reactions (including cutaneous lupus erythematosus) have been described.

SUMMARY

A high level of clinical suspicion is critical in the diagnosis of PPI-induced hypersensitivity reactions. Physicians should be aware of the possible hypersensitivity reactions due to PPI and routine/empirical prescription for PPI should only be used when clinically indicated.

The association between DRESS and the diminished numbers of peripheral B lymphocytes and natural killer cells

Drug reaction with eosinophilia and systemic symptoms (DRESS) is a drug-induced, severe multiorgan system reaction whose exact pathogenesis remains unknown. This study aimed at evaluating specific changes in peripheral blood lymphocyte subtypes associated with DRESS during antibiotic treatment. We analyzed six patients with DRESS. A complete blood count and peripheral blood lymphocytes immunophenotyping were carried out at symptom onset and at follow-up visits. Acute-phase reactants and liver enzymes were measured in all patients. Other tests - viral serology, serum immunoglobulin levels, and skin tests were performed when possible. B-cell counts were low in all patients at the onset of DRESS, and natural killer (NK) cells were low in all cases except one. During recovery, B-cell numbers were within a normal range in five patients. In one, there was even a 10-fold increase in B-cell counts, although the level was mildly low after 3 months. NK-cell numbers were within a normal range in three patients. The mean numbers of B cells and NK cells were significantly higher in the second samples compared to the values on admission. Serum IgA and IgM levels were low in one patient. The drug provocation test was positive with cefotaxime in one patient. Viral serology, performed on five patients, was negative. A decrease in B-cell and NK-cell counts was the most consistent finding associated with the onset of antibiotic-induced DRESS in our patients. This immunologic alteration might be a useful predictor of DRESS development.

The 10th anniversary of the Junior Members and Affiliates of the European Academy of Allergy and Clinical Immunology

This year is the 10th anniversary of the European Academy of Allergy and Clinical Immunology (EAACI) Junior Members and Affiliates (JMAs). The aim of this review is to highlight the work and activities of EAACI JMAs. To this end, we have summarized all the initiatives taken by JMAs during the last 10 yr. EAACI JMAs are currently a group of over 2380 clinicians and scientists under the age of 35 yr, who support the continuous education of the Academy's younger members. For the past decade, JMAs enjoy a steadily increasing number of benefits such as free online access to the Academy's journals, the possibility to apply for Fellowships and the Mentorship Program, travel grants to attend scientific meetings, and many more. In addition, JMAs have been involved in task forces, cooperation schemes with other scientific bodies, organization of JMA focused sessions during EAACI meetings, and participation in the activities of EAACI communication platforms. EAACI JMA activities represent an ideal example of recruiting, training, and educating young scientists in order for them to thrive as future experts in their field. This model may serve as a prototype for other scientific communities, several of which have already adapted similar policies.