An increase in resistance can maintain and even increase infestations.
A thorough study of French over the counter head lice treatments conducted in 2024
revealed ‘the French market for lice products is mainly occupied by treatments with a lack of
effectiveness’. Something the UK is seeing as well.
The study states ‘An increase in the resistance of head lice to neurotoxic therapies,
combined with a partial efficacy of certain suffocating agents, can contribute to the
maintenance or even rise in infestations.’ Ineffectiveness means the infestation picks itself
back up and proliferates whilst the consumer thinks the product had solved the infestation for
them.
The study highlighted the fact that there is ‘no uniform regulatory framework for these
products, and their market authorisation varies according to their mode of action.’ It
concludes that ‘The lack of solid evidence for the efficacy of many topical head lice
treatments makes it difficult for consumers and healthcare providers to make informed
decisions and often leads to a proliferation of insufficiently effective therapies.’
The study also raised concern about the use of certain dimethicone’s like D4
(octamethylcyclotetrasiloxane) and D5 (decamethylcycopentasiloxane) saying ‘They persist
in the ecosystem and accumulate in aquatic environments, contributing to long-term
ecological damage. In addition, research has indicated that D4 may have adverse effects on
human health, including potential impacts on fertility, raising further concerns about the
widespread use of highly concentrated silicones in lice treatment.’ For people using these
types of dimethicone products who are concerned about the use of chemicals on the child or
children, that is certainly important food for thought.