If you have just received a notification from the school announcing an outbreak of head lice, it is very likely that whenever your child will be scratching his head you’ll begin to think that he has head lice.

In order to avoid an overreaction and a wrong diagnosis, it is crucial that you understand what are the symptoms of head lice.

The 2 major symptoms of head lice

First, it is important to understand that a symptom is not equivalent to a disease. Having a symptom does not mean you have the associated disease, and many different diseases can be associated to the same symptom.

A symptom is something not normal in the body functioning noticed by a patient, indicating the presence of a disease or abnormality.

As far as head lice is concerned, there are only two major head lice symptoms, and these are:

  1. An itchy scalp caused by head lice bites.
  2. A tickling feeling of something moving or crawling in the hair.

Sores on the head can be a sign of head lice, but it is less commonly observed.

Seeing a living louse or a nit on the hair is not a symptom, it is already a diagnosis of head lice.

Sometimes there are no head lice signs at all

There might be no symptoms of head lice at all. Sometimes the infested person will not feel anything move in his head, and his scalp will not scratch either. We regularly see kids that start having symptoms only 4 to 6 weeks after being infested. Why?

When the louse feeds on our scalp it needs to inject an anticoagulant to prevent the blood sucked from clotting, and the itching symptom is caused by the allergic reaction to this anticoagulant contained in the saliva of head lice when they bite our scalp.

And not everyone is allergic to this substance, anyway not to the same degree. This is why some people will not have any itching symptom at all.

So, how do you know if you have head lice?

This question is crucial and it is often not being answered properly, although the answer is actually very simple and straightforward.

When we say that the main symptom of head lice is an itchy scalp, this does not mean that you have been infested by head lice whenever your scalp is itching. And this is why so many people make a wrong diagnosis of head lice when they actually have something completely different. Again, a symptom is not equivalent to a disease.

Having an itchy scalp might as well mean that you have dandruff (which is the case on the picture above).

You have head lice when you have at least one living adult louse on your hair.

According to studies, having a few nits ONLY does not mean you will have a lice infestation.

If you can only identify dead adult lice or dead nits, these are signs of a past infestation, not an active one.

What does it mean if you cannot see any live lice or nits but your scalp is itching?

Well first of all, it means you don’t have head lice, which is always a good news! Then, it is possible that the cause of the irritation may be some other type of biting insect or mite, or dandruff. It could be various insects such as mosquitoes, fleas, bedbugs.

Itching and irritation in some cases may also be due to hair care and laundry products, industrial fibers, some underlying disease, or even to a previous anti-lice treatment.