Lice eggs are small and can be difficult to spot. There are 3 species of lice that lay eggs on humans. Each species lays its eggs in different parts of the body:
- Head lice (hair on the head)
- Crabs (pubic hair)
- Body lice (clothing)
What all lice eggs have in common is that they:
- are very small and can be hard to spot
- do not move from the material they are placed on (hair or clothing)
Lice also always lay their eggs directly on their host or in their host's clothing (depending on the species).
Head lice eggs
Head lice eggs are small, oval and white. They sit on the hair roots of the scalp and are attached to hairs. Lice never attach more than one egg per hair. Female lice prefer to lay their eggs in the back of the head, especially behind the ears and on the nape of the neck.
A female louse lays 6-7 eggs per day and between 50 and 100 eggs in her lifetime. The eggs hatch after 5 - 11 days at a temperature of 35 - 37.8°C. If the temperature is below 23°C, the eggs do not hatch.
The newly hatched lice must ingest blood within 24 hours of hatching to survive.
When people find lice eggs in their hair, they often wonder if they are hatched eggs (i.e. empty lice eggshells) or unhatched eggs (i.e. new eggs to be hatched).
Since human hair grows 2 - 3 cm per month, any eggs found 1 - 1.5 cm up the hair shaft are at least 12 days old. These eggs are usually already hatched. If they haven't hatched, they won't hatch in the future because they are already too old.
Lice eggs from head lice should be removed with a lice comb, which should be used in combination with lice repellent or conditioner. In addition, you should also wash clothes and bedding and clean your home to fight lice effectively.
You can read more about head lice here.
Bat eggs are usually laid on the stray hairs in the pubic hair around the genitals. However, they can also be found in other areas of the body where the hairs are straight, such as the beard, eyelashes or armpits. Head hairs are usually not straight enough for crabs to lay their eggs.
The female aphid lays around 3 eggs per day and between 15 and 50 eggs in her lifetime. The eggs stick to hair and are contained in small sacs that are light brown in color. When the eggs hatch (after 6-10 days), the empty egg sacs are white.
This is followed by three nymph stages, which last 27 - 33 days in total and end in the adult stage. A crab develops from egg to adult in 33 - 43 days. Adults live for up to 30 days. They feed exclusively on human blood and ingest blood 4-5 times a day.
Adult crabs and their eggs are controlled with prescription lice repellent.
You can read more about crabs here.
Body lice eggs
Body lice eggs are small, white and oval-shaped like head lice eggs, but unlike head lice, body lice almost always lay their eggs in clothing. They are especially found in the seams and folds of clothing, where adult lice also live. The eggs, as well as the lice, are found in places where clothing is close to the body. The eggs stick to clothing fibers. However, in some cases, body lice can also lay eggs in body hair.
A body louse lays 200-300 eggs in its lifetime and between 6 and 9 eggs per day. The eggs hatch within 5-10 days, but if clothes are removed in the evening (and thus removed from body heat), it can take up to 2 weeks for them to hatch.
Because eggs are primarily laid in clothing, they are removed during laundry. The water temperature should be at least 55°C and clothes should be washed for at least 20 minutes. Adult body lice are controlled in the same way.
You can read more about body lice here.
See also our article on the life cycle of lice here.