Traitement de la gale : des recommandations générales aux applications pédiatriques

[Evaluation of practices in the management of scabies in children]

BACKGROUND

Scabies has been on the rise in France in recent years and has posed therapeutic problems, mainly due to the withdrawal of benzyl benzoate. The objective of this study was to describe prescribing practices for scabies in children.

METHODS

A national survey was conducted by means of a standardized questionnaire covering various clinical situations of scabies and the drugs used preferentially according to age, which was sent out between December 2014 and March 2015 to members of the clinical research group of the French Society of Paediatric Dermatology.

RESULTS

Of the 38 experts contacted, 20 replied. For a typical case of scabies, 55% of the experts initially prescribed oral ivermectin for children aged 6 years, 15% prescribed ivermectin in children aged 2 years, and 5% in infants aged 3 months. Ivermectin was more widely prescribed after failure of prior treatment or recurrence of scabies, on skin lesions or impetigo, if precarious, especially for profuse hyperkeratotic scabies. A total of 35% of the experts reported no prescribing restrictions with regard to patient age or weight. Discrepancies were observed concerning the mode of administration and the time between consecutive doses. Esdepallethrin remained the preferred local treatment among the experts (38% of all topical prescriptions) except in asthmatic children, while permethrin was the least-prescribed topical agent.

DISCUSSION

This study confirms the heterogeneity of our practices. Formal expert recommendations are awaited, particularly concerning the use of ivermectin in infants.

[Safety of oral ivermectin in children]

Ivermectin is an antiparasitic drug, a derivate of avermectins, and a product of fermentation of an actinomycete, Streptomyces avermitilis. Its structure associates two avermectins. Ivermectin acts on the chloride-dependent channels of both glutamate and γ-aminobutyric acid, interrupting neurotransmission in invertebrates. In humans, several mechanisms of brain protection exist, including P-glycoprotein, present on the apical face of endothelial cells of the blood-brain barrier and coded by the MDR1 gene. Ivermectin is presently used in mass treatment of onchocerciasis, other filariasis, some intestinal nematode infections, but also in scabies, and more rarely in resistant head lice. The side effects described are related to the release of antigen and cause an inflammatory reaction. Studies conducted in children or infants have shown good tolerance of ivermectin. However, its use in infants who weigh less than 15kg is a problem because of the absence of marketing authorization for this age group. However, the risk of excessive and uncontrolled use in head lice requires close surveillance.

[Treatment of scabies and Ascabiol(®) supply disruption: what about the pediatric population?]

Scabies is a disease in steady increase in Île-de-France region. Standard treatment, Ascabiol(®) (benzyl benzoate/sulfiram), is back-order for several months and its return remains uncertain. Facing this drug shortage, French Drug Agency (ANSM) has imported a drug from Germany, Antiscabiosum 10 % (benzyl benzoate), to treat patients having contraindications for other scabicides available in France (ivermectin, esdepallethrine). However, infants less than 1 year (<15 kg) and asthmatics infants have no alternative treatment. A multidisciplinary workgroup explored the various existing therapeutic alternatives in France and worldwide. From ANSM's recommendations and group's experience, a decision algorithm was proposed for treating patients. However, pediatric context implied the use of off-label drugs. Proposed treatments widely known by practitioners, prescriptions-types, dose, modalities of use and dispensation, and flyers to patients were realized to optimize treatment efficacy.