Is there an interest for hair analysis in non-intentional pediatric cannabis intoxication?

•Hair testing shows indirectly the intensity of children’s environmental exposure.•39 % of the children could be considered exposed to an intensely toxic environment.•Children intensely exposed weighed less than other exposed patients.•Family of children intensely exposed had more social issues. The incorporation of drugs in the hair of young children differs from that of adults and the metabolism of cannabis cannot be the same. Our primary objective was to analyze the distribution of the different cannabinoids in children’s hair samples. The secondary objective was to correlate the intensity of toxic environmental exposure to cannabinoid metabolite levels. This was a prospective, single-center, observational pilot study of a pediatric cohort. Included subjects were all children less than 6 years of age admitted to a tertiary pediatric emergency unit for proven cannabis intoxication during the reference period. A hair strand was sampled within 12h of emergency admission. Forty-one pediatric patients were consecutively enrolled. Hair analysis showed that 34 children were positive for Δ9-THC (range 0.06–284.4ng/mg); 41 % of them were also positive for THC−COOH (range 0.26–2.76pg/mg). Depending on the Δ9-THC concentration (>1ng/mg), 39 % of the children could be considered exposed to an intensely toxic environment. The rate of THC−COOH detection steadily increased from 2015 to 2018 (18 %, 40 %, 50 %, 58 % for each consecutive year). Children intensely exposed weighed less on admission (p=0.02), had more comatose presentations (p=0.02), and more previous social issues (75 % versus 12 %, OR 22.0, p=0.0002). Hair testing in this context indirectly shows the intensity of children’s toxic environmental exposure by the cannabinoid metabolite threshold. This was very helpful during the collegial examination of the toddlers’ environment and led to a full investigation and to appropriate decisions concerning social measures.