Head lice can be difficult to treat due to their high reinfection rate and ability to develop resistance to the insecticides in some treatments. Head lice are unlikely to develop immunity to silicone or oil-based formulations as these have a physical action, rather than a chemical one. NB: No treatment method will be effective if head-to-head contact is made with an infected person during the treatment period.

Wet combing (e.g. Nitty Gritty Nitfree Comb)

The wet combing removal method is the same procedure as that used for detection. This should be repeated on days five, nine and 13 so that young lice are cleared as they hatch, before they can reach maturity. The procedure should be repeated until no live lice are found for three consecutive sessions. For wet combing to be effective, it needs to be carried out regularly and thoroughly. The length of time it takes to comb the hair depends on how long and thick the hair is. This method is suitable for all ages and as it involves no chemicals or insecticides, there is no risk of skin irritation or lice resistance.

Non-insecticide treatments 

Dimeticone (e.g. Hedrin 4% Lotion, Hedrin Once Spray Gel, Lyclear Spray) works by blocking the tiny holes (spiracles) that head lice breathe through, leading to suffocation and dehydration. Dimeticone can be sold OTC for adults and children aged over six months. It is also suitable for those with skin conditions and asthma. It should be applied twice, seven days apart. The lotion formulation should be left on the hair and scalp for at least eight hours, or overnight, and then washed out using a normal shampoo. The spray gel should be applied as instructed and left on the head for at least one hour.

Isopropyl myristate and cyclomethicone (e.g. Full Marks Solution) also works by blocking spiracles. It should be applied twice, seven days apart to dry hair for 10 minutes. The hair should then be systematically brushed with a fine-toothed comb to remove lice. These products are not suitable for children younger than two years or for anyone with a skin condition. However, it can be used by people who have asthma.

Coconut, anise and ylang ylang spray should be applied twice, seven days apart and left on for 15 minutes before the hair is shampooed and combed to remove lice. It is not suitable for children younger than two years old, or individuals with skin conditions or asthma. The above treatment options have a physical mode of action. It is therefore unlikely that lice will develop resistance to them.

Insecticide treatments 

Malathion (e.g. Derbac-M) €“ water-based preparations of malathion are suitable for customers from six months of age and those with asthma. They can be used by pregnant women or those who are breastfeeding, but only if other treatment options have failed. Derbac-M should be applied to the hair and scalp until thoroughly moistened. The hair should then be left to dry naturally in a warm, well-ventilated room and shampooed out after 12 hours.

Permethrin (e.g. Lyclear Crème Rinse) works in 10 minutes and is suitable for use from six months of age. All medicated treatments should only be applied if a living head louse is found.