Often there is no sign of infestation until nits, which are hatched empty egg cases, start to become visible within the hair. In most cases, itching is the main symptom of head lice, which is not caused by the lice biting the scalp but by an allergy to the lice saliva. However, not everyone experiences itching and it can take up to three months to develop this allergic reaction to the lice saliva. In some cases, a rash may appear on the back of the neck. This is caused by a reaction to lice droppings.
Further symptoms include a red rashes and little red bumps as well as difficulty sleeping – this due to lice crawling through the hair.