Head lice are something many parents and children encounter sooner or later. Although they may seem harmless at first glance, these tiny parasites can cause significant itching and irritation. They spread especially quickly in environments like primary schools, where children play and learn in close proximity. In this blog, we take a closer look at what head lice actually are, how to recognize them, how to get rid of them with 100% guarantee – either through a home treatment or a clinic treatment – and much more practical information.
What are head lice?
Head lice are parasites that live exclusively on humans. A louse cannot survive on an animal; you cannot get or transmit head lice through contact with animals.
An adult louse is approximately the size of a sesame seed and is brownish-gray of color.
Lice have a flat body with 6 legs and 2 small antennae.
Their body is divided into an upper and a lower part, with the upper part being significantly smaller. The six legs are attached to the upper body.
The female is slightly larger than the male – because she needs to be able to carry up to eight eggs – and can be distinguished by the shape of her rear end.
.png)
How do lice spread?
Lice have no wings, so they cannot fly.
They also lack legs designed for walking on surfaces or for jumping.
They can only climb from hair to hair.
However, they are highly skilled climbers. Using one or a few legs to grasp one hair, they use the other legs to sense where the next hair is to climb onto.
This allows them to move over distances of up to 30 centimeters, so from one side to the other side of your head, per minute.
They make use of their claws located at the ends of their six legs, which fit perfectly around a hair, allowing them to hold on tightly to your hair.
So, even when you brush, comb or wash your hair, run your hands through it, or rub your head against a pillow, a louse won't fall out of your hair as a result.
Since lice cannot fly, jump, or walk on surfaces and are found only in hair, the only way to contract head lice is through hair-to-hair contact. This is almost always through direct hair-to-hair contact, and sometimes via hairs left on objects. More information on this topic can be found on our "Transmission" page.
Can lice swim?
Lice cannot swim; however, they can float.
Lice do not have lungs like mammals.
Like most insects, lice breathe through small openings on the sides of their body, called tracheae.
They can close these openings to hold their breath for up to 8 hours.
This is why lice do not drown when you shower, wash your hair or swim.
.png)
Lice will not let go of their host to try to swim to another person.
They are incapable of actively swimming toward someone, and they will not take the risk of not finding a head of hair by drifting with currents or water movement.
Getting infested with head lice in a pool or lake is therefore practically impossible, unless there is direct hair-to-hair contact.
How do lice survive?
An adult head louse drinks about 0.0005 to 0.0007 milliliters of blood per meal – extremely little, far less than a milliliter.
Lice feed multiple times a day, including at night, averaging 4 to 6 meals per 24 hours.
This means that one head louse consumes a total of approximately 0.002 to 0.004 milliliters of blood per day.
Even in a very heavy infestation with, for example, 1.000 lice, this would amount to a maximum of 2 to 4 milliliters of blood per day.
This is still a very small amount and does not pose any risk of blood loss in a person, even with thousands of lice on the head.
They have a piercing mouthpart that allows them to puncture the skin without you feeling it. Lice inject a small amount of their saliva into the bite to keep the blood flowing and ensure they can drink enough.
In addition to the host's blood, a louse also requires the body heat and humidity of the host's scalp.
Outside this microclimate, a louse can survive 24 to 48 hours, depending on the environment, while nymphs are even more vulnerable and usually survive for a shorter time. This is due to physiological limitations: loss of body fluids reduces the louse’s muscle function and energy supply, making it less effective at crawling and gripping.
Ectoparasites such as lice have a limited ability to compensate for water loss outside their host. As a result, their survival capacity decreases sharply and their activity diminishes. A healthy, strong louse therefore resides exclusively on the head of a host; only a weakened louse that is no longer able to hold on can end up outside the host. This combination of biological traits and survival instinct – which has ensured their survival for thousands of years – ensures that a louse will never voluntarily leave its host.
What is a nymph?
The newly hatched lice are called nymphs.
In the beginning, they are as small as a nit. To the naked eye, they appear as moving specks of dust.
Lice have an exoskeleton, just like a crab or a lobster.
As the (soft inside of the) young nymph grows, the external rigid shell eventually becomes too small.
To free themselves from the constricted "jacket, the nymph molts.
The nymph undergoes this molting process three times in a period of ten days – the first time at 2 days after hatching, the second time 3 days later and the third time 5 days later – after which it has become an adult louse.
When a recently molted nymph sheds its exoskeleton, it is almost transparent, so the blood it has consumed can be seen, making the nymph appear red.
Nymphs are usually found very close to the scalp because it is warm and humid there—exactly the conditions they need.
Because of their small size and their position at the scalp, nymphs are often missed during combing treatments, slipping easily through the tapered tips of the nit comb teeth. When nymphs are missed, they have the chance to develop into adult lice that can reproduce, continuing the infestation cycle.
There is a special “Comb Cream” that effectively addresses this problem. The cream covers the scalp and traps lice and nymphs within its texture, like an avalanche, making it easy to comb them out completely, cream and all.
What is a nit?
The eggs of head lice are called nits. A nit is only 0.8 millimeters long.
A female head louse needs to mate only once with a male and can lay between 100 and 150 eggs in her lifetime.
Nits are attached extremely firmly to the hair.
The adhesive is not only strong, but it is also applied all around the hair shaft, preventing the nit from being pulled sideways or slid off the hair.
Only with a very good nit comb is it possible to detach the nit and slide it off the hair. Nits can remain firmly attached for months, up to a year, even after the egg has hatched or if the embryo inside the egg has died.
In the picture below, you can see a nit with a "tail." This "tail" is the adhesive that surrounds the hair shaft like a casing.
The louse always lays its eggs very close to the hair roots, where they can develop into young lice thanks to the warm and humid environment of the scalp.
Eggs that are located more than a few millimeters from the scalp were laid more than 10 days earlier and therefore cannot contain live embryos, as eggs always hatch within 10 days.
.png)
Fortunately, not all nits hatch, which is exactly why the louse lays so many—to ensure its survival.
However, it is important to kill or remove every viable nit to eliminate an active infestation.
Since lice shampoos or lotions never kill all the eggs with certainty, and even combing with a nit comb usually misses some nits, it is essential to comb with the right tools over a period of 14 days to break the infestation cycle. By doing this, newly hatched lice (nymphs) are continuously removed before they can lay new eggs, eventually breaking the cycle.
Daily combing with a regular nit comb and conditioner for 14 days only provides a 38%–57% chance of success.
Therefore, it is important to use a high-quality nit comb with teeth that do not spread apart, in combination with a special Comb Cream, so that lice, nymphs, and eggs are effectively removed and the cycle is guaranteed to be broken—even when combing every other day for 13 days instead of daily.
Of course, if you don’t have the time or patience to wait 13 days to become lice-free, there is always the option of visiting Lice Clinic Europe, where the entire infestation is eliminated in 60 minutes with an absolute guarantee.
One treatment, no follow up check, no follow up treatment, no hassle.
What is the difference between brown and white nits?
A nit is a transparent egg containing an “unborn” louse: the embryo. The embryo is brown, which gives the nit its brown appearance. After 7 to 10 days, the egg hatches, leaving behind an empty, transparent shell that appears white.
In other words, white nits are empty eggs, while brown nits contain a (potentially live) embryo.
Sometimes, you may also see eggs that are partially filled and partially empty. These are nits with an embryo that did not fully develop and has died. A dead embryo, of course, cannot hatch and remains inside the egg, where it gradually shrivels. This explains the empty portions seen within the egg.
Frequently, dandruff is mistaken for white nits. There is even a type of dandruff that clings to the hair shaft like a cylinder. Because this type of dandruff closely resembles white nits, it is also referred to as pseudo-nits (see the photos below).
How can I tell if a nit is still viable?
A nit is potentially viable if it meets all 3 of the following criteria:
-
The nit is located within a few millimeters of the scalp.
-
The nit is firmly attached to the hair.
-
The nit is entirely light to dark brown in color.
For more information on how to determine if you have an active head lice infestation, please visit our Diagnosis page.
