Allergy to betalactam antibiotics in children: a prospective follow-up study in retreated children after negative responses in skin and challenge tests

BACKGROUND

Up to 10% of the patients in whom suspected betalactam hypersensitivity (HS) has been excluded by skin and challenge tests report suspected allergic reactions during subsequent treatments with the same or very similar betalactams. It has been suggested that the reactions may result from a resensitization induced by the challenge performed at the time of the allergological work-up. However, most patients did not undergo a second allergological work-up, to determine if the reactions resulted from betalactam HS or not.

OBJECTIVES

We aimed to determine if children diagnosed nonallergic to betalactams have tolerated subsequent treatments with the initially suspected and/or other betalactams, and, in case of a reaction, if the reaction resulted from betalactam HS.

METHODS

We sent a questionnaire concerning the clinical history of their children to the parents of 256 children previously diagnosed nonallergic to betalactams. A second allergological work-up was performed in the children reporting suspected allergic reactions during subsequent treatments with the same and/or other betalactams. Skin tests were performed with the soluble form of the suspected (or very similar) betalactams and other betalactams from the same and other classes. Skin test responses were assessed at 15-20 min (immediate), 6-8 h (semi-late) and 48-72 h (late). Oral challenge (OC) was performed in children with negative skin tests, either at the hospital (immediate and accelerated reactions), or at home (delayed reactions).

RESULTS

A response was obtained from 141 children (55.3%). Forty-eight (34%) of those children had not been treated with the betalactams for whom a diagnosis of allergy had been ruled out previously. Seven (7.5%) of the 93 children who had been treated again reported suspected allergic reactions. Skin tests and OC were performed in six of those children, and gave negative results in five children. In one child previously diagnosed nonallergic to amoxicillin associated with clavulanic acid, we diagnosed a delayed HS to clavulanic acid and a serum sickness-like disease to cefaclor. Thus, the frequency of reactions resulting from betalactam HS in children with negative skin and challenge tests is very low, and does not exceed 2.1% (2/93) if we consider that the child which refused a second allergological work-up is really allergic to betalactams.

CONCLUSION

Our results in a very large number of children show that reactions presumed to result from betalactam HS are rare in children in whom the diagnosis of betalactam allergy has been ruled out previously. Moreover, they suggest that, as shown for the initial reactions, most of the reactions during subsequent treatments are rather a consequence of the infectious diseases for whom betalactams have been prescribed than a result of betalactam HS. Finally, they suggest that the risk of resensitization by OC is very low, and do not support the notion that skin testing should be repeated in children diagnosed nonallergic to betalactams.

Plasmodium falciparum CS C-terminal fragment: preclinical evaluation and phase I clinical studies

Preclinical evaluation of synthetic peptides corresponding to the C-terminal regions of the circumsporozoite (CS) protein in various Plasmodia showed that these preparations were immunogenic and safe upon injection in various animal models. Additionally, the corresponding peptide from Plasmodium falciparum was widely recognized by sera and PBL obtained from semi-immune adults living in malaria endemic areas. Moreover, the CS C-terminal peptide derived from P. berghei conferred protection upon challenge with live sporozoites in mice. A GLP preparation of the synthetic peptide corresponding to residues 282-383 of the Pf CS, NF-54 strain is currently evaluated in a open, non-randomized, Phase I human trial. Data obtained after the second antigen injection show that the malaria vaccine Pf CS 282-383 is safe, well tolerated and gives rise to high antibody titre, CD4+ and CD8+ lymphocyte responses.

[Inhaled steroids effect on bones]

Inhaled corticosteroids (ICS) are the mainstay of asthma treatment, when an antiinflammatory agent is warranted. The development of the ICS has permitted to diminish the adverse effects associated with oral steroids and with equipotent doses there are less adverse effects with ICS on bone metabolism compared to oral steroids. There is now reassuring evidence that doses of < or = 400 micrograms for children and < or = 1000 micrograms for adults are safe and do not appear to have clinically significant adverse effect on bone density or bone growth. When exceeding the recommended thresholds for more than 3 months, osteoporosis prevention would be appropriate. Furthermore a mineral bone density measurement might be done in this context in order to identify those persons who are at risk of developing or worsening preexisting osteoporosis. Growth monitoring is justified in any child taking ICS. Biochemical markers of bone formation and resorption might give complementary information to the mineral bone density measurement. The addition of a leukotriene receptor antagonist and or of a chromone may allow a reduction in the requirement for ICS in mild to moderate asthma. Finally the achievement of an increased glucocorticoid potency combined with an improved airway selectivity and a shorter plasmatic half-life of the ICS will further contribute to diminish their effects on bone metabolism.

[The anti-leukotrienes: a new class of drugs to integrate into the therapeutic strategy of asthma]

Leukotrienes play an important role in the pathogenesis of asthma, a chronic inflammatory disease. They are potent bronchoconstrictors and chemoattractants; furthermore, they increase vascular permeability and mucus secretion. Early treatment of bronchial inflammation has become an essential element of the therapeutic approach of asthma and relies mainly on inhaled corticosteroids. However, known adverse effects of inhaled corticosteroids raise important long-term questions on their local and systemic tolerance. These safety aspects have encouraged the development of other anti-inflammatory drugs. Antileukotrienes (specific antagonist of receptors and inhibitors of 5-lipoxygenase) display a beta 2-agonist additive effect, confer an effective protection in bronchial provocations, improve both clinical and functional asthma scores and also allow a decreasing in short-acting beta 2-agonist use. They are intended for patients suffering from persistent mild-to-moderate asthma. However, further studies are still required to determine both their long-term efficacity and tolerance, to define their place in the strategy of asthma management and finally to clarify their application in other allergic diseases.