Find a Registered Dental Hygienist


Knowledge Network

FACT SHEET: Head Lice (also known as “nits” and “pediculosis”; caused by the head louse ectoparasite Pediculus capitis1)

Date of Publication: March 11, 2013

Is the initiation of non-invasive dental hygiene procedures* contra-indicated?

  • No.

Is medical consult advised?  

  • Yes. While a medical consult for oral health reasons is not required, a referral to a primary care provider (e.g., physician or nurse practitioner) is appropriate for definitive diagnosis and treatment (e.g., treatment with permethrin or pyrethrin “shampoo”).

Is the initiation of invasive dental hygiene procedures contra-indicated?**

  • No.

Is medical consult advised? 

  • Yes; see above.

Is medical clearance required? 

  • No.

Is antibiotic prophylaxis required?  

  • No.

Is postponing treatment advised?

  • Possibly, because some dental hygiene procedures involve being in close contact.

Oral management implications

  • Mode of transmission is most commonly by close person-to-person contact. Although uncommon, head lice can also be spread by lying on a bed or couch that has recently been in contact with an infested person. Similarly, spread can occur via shared headgear. Cats, dogs, and other pets do not play a role in transmission of human lice. 
  • Avoid direct contact with infested hair.

Oral manifestations

  • None

Related signs and symptoms

  • While head lice are almost exclusively found on the scalp (particularly around and behind the ears and near the neckline at the back of the head), they are occasionally found on the eyelashes or eyebrows.
  • Adult head lice are about 2−3 mm long. They attach their greyish-white eggs (“nits”) to the base of the hair shaft. Lice move by crawling; they do not jump or fly.
  • Itching is caused by an allergic reaction to the bites of the head louse. If the patient/client has been scratching, sores on the head may be evident. Because head lice are particularly active at night, the infested person may be irritable from lack of sleep.
  • Head lice are most common among preschool children who attend child care, as well as among elementary school children and the household members of affected children.

References and sources of more detailed information

Date: December 10, 2012
Revised: January 31, 2020


1 Body lice infestation (typically of the clothing, especially along the seams of inner surfaces) is caused by body louse Pediculis corporis. Crab lice (Phthirus pubis) usually infest the pubic area and, more rarely, facial hair (including eyelashes in heavy infestations), axillae, and body surfaces. The body louse is the species that is involved in outbreaks of epidemic typhus, trench fever, and epidemic relapsing fever. Such louse-borne diseases are not a concern with head lice.

* Includes oral hygiene instruction, fitting a mouth guard, taking an impression, etc.
** Ontario Regulation 501/07 made under the Dental Hygiene Act, 1991. Invasive dental hygiene procedures are scaling teeth and root planing, including curetting surrounding tissue.