I have bought an amazing electronic nit comb. It buzzes until it finds a nit and then the buzz is interrupted until the nit has been zapped and falls out of the hair dead.
Hours of pleasure. I'd recommend one even if nits don't visit your house. You could chase ants with it, for example.
Sorry I needed an antidote after that last post!
After years of battling....this is my definitive answer to the nit problem: for complete nit blasting and prevention:
Hedrin Once to get rid of nits.
Then buy a water spray bottle (Superdrug sell them) and fill it with water plus a few drops of lavender essential oil. Spray your child's hair before they go to school. Nits hate lavender. Alternatively, tea tree oil shampoo also seem to prevent infestations!