Head lice are more commonly found in children but adults can have them too.
They cannot jump and they can only spread by people touching heads, usually for some time. Head lice found on pillows, hats, etc are generally thought to be incapable of infecting a person and usually die within 24 hours.
Infection may be symptomless in children, whereas in others there will be an itchy scalp, especially behind the ears. This itch can take a few weeks to develop after infection, as it is due to an allergic response to the lice, and by the same token the itch may persist for some time after successful eradication with insecticidal lotions.
Infection can only be reliably diagnosed when a louse is found, and this can only be successfully done by detection combing.
Use of insecticidal lotions should only be used once live lice have been found by detection combing. If no lice have been seen, treatment is unnecessary. The use of insecticidal lotions as a preventative measure is not recommended. Insecticidal products should not be used for babies under 6 months old.
No evidence exists of the efficacy of herbal treatments or aromatherapy. Clinical trials showing the effectiveness of wet combing (Bug Busting) have received mixed reception.
Treatment of head lice requires a huge commitment from both patients and parents. Resistance to lotions can occur, but most apparent treatment failures are due to poor application technique, use of inadequate quantities of lotion, or forgetting that a persistent itch is not necessarily as sign of continued infection. Always follow the instructions of each product as indicated by the manufacturer.
Nit cases (attached to the hair) normally camouflage with the hair colour whilst the lice is alive, once treated the nit case tends to be white in colour. Most treatments will not remove the cases and these have to be physically removed by combing.