Can head lice become resistant to a lice treatment?

Lyclear Shampoo, Sensitive, Lotion and Spray work in a purely mechanical mode of action, which helps prevent them becoming resistant to the ingredients.  

There is a possibility that head lice may become resistant to ingredients of insecticide-based head lice products. However, true resistance to insecticides is relatively uncommon. An apparent treatment failure is more likely to be the result of:

• a bad diagnosis.
• failure to follow instructions: not enough product, treatment duration is too short, lack of head lice and eggs removal by combing, etc.
• (re)-infestation by untreated school friends, family members including adults.
• no cleaning and disinfection of the surroundings.
• not checking 7 days after the first treatment or repeating the treatment if necessary.