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

Date of Publication: March 11, 2013
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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, referral to a primary care provider (e.g., physician or nurse practitioner) is appropriate for definitive diagnosis2 and treatment3.

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?

  • Yes, because many dental hygiene procedures involve being in close contact. Ideally, the patient/client should be successfully treated for head lice before dental/dental hygiene procedures are performed. Although spread to oral healthcare providers, office staff, and other patients/clients is unlikely (including via direct contact in the waiting room), risk can be eliminated by successful head lice treatment in advance of office visit.

Oral management implications

  • Mode of transmission is most commonly by close person-to-person (i.e., head-to-head) contact. Although uncommon, head lice can be spread by lying on a bed or couch that has recently been in contact with an infested person. Indirect spread can also occur via shared pillowcases, headgear, brushes, and combs. Cats, dogs, and other pets do not play a role in transmission of human lice.
  • Avoid direct contact with infested hair.
  • Rescheduling of appointment should be handled with sensitivity.
  • If dental/dental hygiene procedures cannot be deferred until a patient/client’s head lice infestation (i.e., live lice, not just dead nits) has been successfully treated, use of appropriate personal protective equipment (PPE), including a disposable head covering, is important. Standard infection control precautions apply.

Oral manifestations

  • None.

Related signs and symptoms

  • Head lice do not cause illness or spread disease. Having head lice does not mean a person has poor personal hygiene or lives in an unsanitary environment.
  • 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. 
  • A tickling feeling or sensation of something moving in the hair may be experienced.
  • The infested person may be irritable from lack of sleep, because head lice are particularly active at night.
  • 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; January 9, 2026


FOOTNOTES

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 other body surfaces. The body louse is the species that is involved in outbreaks of epidemic typhus, trench fever, and epidemic relapsing fever. Lice are host-specific; species that infect non-human hosts do not infest people, although they may be present transiently.
2 A head lice infestation can be diagnosed by finding live nymphs or adult lice in the hair or scalp. A fine-toothed louse comb may assist in identifying live lice. The presence of nits (eggs) on hair shafts near the scalp suggests but does not confirm infestation.
3 First-line treatment options include permethrin or pyrethrin insecticide shampoo. Non-insecticide options are usually used only if first-line insecticidal treatment fails. Household members should be checked for head lice, and those with lice should be treated.


* 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.