Educational case series: β-lactam allergy and cross-reactivity

SIAIP position paper: provocation challenge to antibiotics and non-steroidal anti-inflammatory drugs in children

Drug hypersensitivity reactions (DHRs) in childhood are mainly caused by betalactam or non-betalactam antibiotics, and non-steroidal anti-inflammatory drugs (NSAIDs). Laboratory tests for identifying children who are allergic to drugs have low diagnostic accuracy and predictive value. The gold standard to diagnose DHR is represented by the drug provocation test (DPT), that aims of ascertaining the causative role of an allergen and evaluating the tolerance to the suspected drug. Different protocols through the administration of divided increasing doses have been postulated according to the type of drug and the onset of the reaction (immediate or non immediate reactions). DPT protocols differ in doses and time interval between doses. In this position paper, the Italian Pediatric Society for Allergy and Immunology provides a practical guide for provocation test to antibiotics and NSAIDs in children and adolescents.

Drug hypersensitivity in children: report from the pediatric task force of the EAACI Drug Allergy Interest Group

When questioned, about 10% of the parents report suspected hypersensitivity to at least one drug in their children. However, only a few of these reactions can be confirmed as allergic after a diagnostic workup. There is still a lack of knowledge on drug hypersensitivity (DH) epidemiology, clinical spectrum, and appropriate diagnostic methods particularly in children. Meanwhile, the tools used for DH management in adults are applied also for children. Whereas this appears generally acceptable, some aspects of DH and management differ with age. Most reactions in children are still attributed to betalactams. Some manifestations, such as nonsteroidal anti-inflammatory drug-associated angioedema and serum sickness-like reactions, are more frequent among young patients as compared to adults. Risk factors such as viral infections are particularly frequent in children, making the diagnosis challenging. The practicability and validity of skin test and other diagnostic procedures need further assessment in children. This study presents an up-to-date review on epidemiology, clinical spectrum, diagnostic tools, and current management of DH in children. A new general algorithm for the study of these reactions in children is proposed. Data are presented focusing on reported differences between pediatric and adult patients, also identifying unmet needs to be addressed in further research.

Antibiotic allergy

Although allergy to β-lactam and non-β-lactam antibiotics is commonly claimed, true allergy to these drugs is often absent. Reactions to antibiotics can be classified according to the interval between the last administration of the drug and the onset of symptoms, but except for immediate reactions occurring within an hour of exposure, which are almost always either IgE-mediated or due to direct stimulation of mast cells, reactions occurring later than 1 hour probably have multiple mechanisms, including being IgE-mediated or involving cell-mediated reactions. The latter are likely caused by drug-specific T lymphocytes. The diagnosis of antibiotic allergy can be difficult.

Skin testing for Beta-lactam antibiotics: impact of the availability of a major determinant

Beta-lactam antibiotics are very effective agents for a variety of infections. In patients with beta-lactam allergy, these drugs are withheld due to fear of subsequent allergic reactions. Therefore, increasing their exposure to broad spectrum antibiotics, which are more costly, have greater side effects, and increase the risk of developing resistant organisms. Up to 90 % of patients with a proposed beta-lactam sensitivity can tolerate beta lactam agents after appropriate evaluation. Skin testing to beta-lactam agents is the gold standard in evaluating patients with type I, immediate hypersensitivity reactions. The robust negative predictive value of this test has yet to be surpassed by any other testing modality currently available.

Desensitization to antibiotics in children

Drug hypersensitivity reactions can occur to almost all drugs and antibiotics are among the most common cause for this kind of reactions. Drug hypersensitivity may affect any organ or system, and manifestations range widely in clinical severity from mild pruritus to anaphylaxis. In most cases, the suspected drug is avoided in the future. In case of infection, there is usually a safe antibiotic alternative. Nonetheless, in some cases, no alternative treatment exists for optimal therapy. Under these circumstances, desensitization may be performed. Drug desensitization is defined as the induction of a temporary state of tolerance to a drug which can only be maintained by continuous administration of the medication responsible for the hypersensitivity reaction. Desensitization is mainly performed in IgE-mediated reactions. Increasing doses of the implicated drug are administered over a short period of time, until the therapeutic dose is achieved and tolerated. Very few studies confined to children are found in literature. Most of them are case reports. In general, the proposed desensitization schemes are similar to those used in adults differing only in the final dose administered. The purpose of this study is to review desensitization to antibiotics in children presenting and discussing three clinical practical cases of desensitization in this age group.

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.