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Baby & child.

Updated: 1 Jul 2021

Nits and head lice: separating fact from fiction

We look at some of the most popular myths surrounding head lice and nits
Which?Editorial team

Head lice have been around for so long, it's no surprise that a whole industry of half truths, myths, old wives tales and random questions have sprung up around them. We've pulled out some of the most common (and some of the strangest) to help you separate fact from fiction.

Find out what parents think are the best methods for getting rid of head lice by reading our guide to the best nit and head lice treatments.

Does olive oil or mayonnaise kill head lice?

Slathering your child's head with items from your kitchen cupboard may seem like an easy quick fix, but scientific evidence to support using mayonnaise or olive oil to kill or even deter head lice is scant. 

Moreover, these methods often require you to wrap your child's head in plastic and leave it on overnight, which is actually quite dangerous, as the plastic bag could become loose and pose a suffocation risk.

Does chlorine in a swimming pool kill head lice?

Chlorine does not kill head lice and submerging your child's hair in any form of liquid including swimming pool water, sea water or fresh water will not kill the lice. Head lice are able to hold their breath for several hours.

Can you kill head lice with hair straighteners?

Hair straighteners will kill any lice or eggs that the hot plates come into contact with. However, most head lice prefer to remain as close to the scalp as possible, rather than along the hair shaft, so you may struggle to get the straighteners close enough to the scalp without burning it.

Can you catch head lice and nits from bedding or sofas?

Head lice can't fly, jump or swim, but they can walk from one person's scalp to another via bedding, or if your heads are close together for any length of time. Lice prefer to be close to their two most important sources: heat and food. This means they prefer to stay close to the scalp, and are unlikely to spend a long time away from it. 

It's not really necessary to put bedding, towels or clothing through a hot wash to kill lice. However, you may still wish to wash them if there are lice droppings or moulted lice skins on them.

Do lice only affect children?

Lice can affect adults as much as children – they have no preference when it comes to the age of a scalp.

Do lice prefer clean hair?

Lice will infect both clean and dirty hair.

Do lice prefer long hair?

Lice will infect all types of hair, but tend to be harder to spot in long hair, so can go unnoticed for longer.

Can lice jump and fly?

Lice can only walk. They have no wings and are unable to jump (like fleas) from person to person.

Can lice be spread by sharing towels?

Lice can only crawl, and usually walk from head to head. It's less likely they'll be spread via sharing clothes or towels, but it can happen occasionally.

If you've got lice will you have an itchy scalp?

Your scalp will only itch if the bites and faeces of lice cause an allergic reaction. Not everybody is allergic to this, so not everyone itches when they have head lice.

Do head lice carry diseases?

Head lice do not transmit diseases, but scratching bites could increase the risk of secondary skin infections.