How to Diagnose Head Lice: Identifying Lice Eggs, white Nits on Fingers and Scalp

Head lice are very tiny insects, measuring 0.08-0.12inch / 2-3mm, i.e. the size of a sesame seed. Thus, they are very hard to see with the naked eye, also because they move about the hair rather quickly. Only if you use a good head lice comb are you able to detect whether you have head lice or not.

The louse egg, white nits is easier to spot in the hair. The appearance of the louse egg varies from whitish to brownish. The egg is oval in shape and measures 0.03inch / 0.8mm. The eggs are glued to the hair and do not fall off even if you shake the strand of hair. The hatched eggs (called nits and white nits) are white and can be inches away from the scalp, as they grow away from the scalp as the hair grows.

Living and dead Lice and Nits

The nits do not fall off the hair by themselves, so if you want to remove the egg, you will have to remove the egg with your fingernails or use a special nit comb with very narrow distance between the teeth. Furthermore, research is being done for finding new products, which are able to loosen the eggs’ glue or colour the eggs, so they are easier to comb out of the hair.

Just because you find nits, it is not certain that you have live head lice. It can be difficult to determine whether the eggs you find on the strand of the hair are dead, alive or hatched. If you only see eggs and no live head lice, there is no need to start a treatment. However, it is important that you check the hair regularly during the next 14 days to watch for live head lice hatching from the eggs.

When you check for live head lice, it is not enough to search the hair with your fingers. The most efficient method is to use a proper head lice comb. It is four times more efficient and takes half the time.

The distance between the teeth of the comb must not exceed 0.008inch / 0.2mm. Otherwise it will not catch the smallest nymphs. At the same time, the distance between the teeth must be exactly the same between all the teeth. You will find many poor head lice combs on the market, which have never been tested if they can catch head lice at all. Ask your local pharmacy or drugstore which head lice comb to choose. You can see some examples of clinically proven head lice combs here.

Combing can be done in both dry and wet hair. However, studies have shown that if you carry only a few head lice (10 or less), you are more successful detecting them when conditioner is applied to the hair before combing. This prevents the head lice from moving around, thus making it easier to catch them with the head lice comb – and it also makes it considerably easier to comb the hair.