FACT SHEET: Scabies (also known as “sarcoptic itch” and “sarcoptic acariasis”; caused by the human parasitic itch mite Sarcoptes scabei, var. hominis)
Date of Publication: August 7, 2014
Is the initiation of non-invasive dental hygiene procedures* contra-indicated?
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 a topical prescription scabicide, such as 5% permethrin cream/lotion or alternatives). In addition to the infested person, treatment is also recommended for household members, sexual contacts, and other persons who have had prolonged skin-to-skin contact with an infested person. In the case of Norwegian scabies (see below), treatment is recommended even with brief skin-to-skin contact.
Is the initiation of invasive dental hygiene procedures contra-indicated?**
Is medical consult advised?
- Yes; see above.
Is medical clearance required?
Is antibiotic prophylaxis required?
Is postponing treatment advised?
- Yes, until after patient/client has been successfully treated, because some dental hygiene procedures may involve being in close contact.
Oral management implications
- Mode of transmission of parasites occurs most commonly via prolonged direct contact with infested human skin and also during sexual contact. Less frequently, transfer from clothes, towels, and bedding may occur, but only if they have been contaminated by infested persons within 48 to 72 hours beforehand. Mites can burrow below the skin surface in fewer than 3 minutes. Typically, fewer than 10 to 15 mites are present on the entire body of an infested person who is otherwise healthy. However, people with the uncommon form of infestation known as Norwegian scabies (“crusted scabies”) are very contagious, because of the huge number of mites (up to 2 million) present in exfoliating scales.
- Animals do not spread human scabies.
- If a person has never had scabies before, symptoms such as itching usually take 2 to 6 weeks to begin. In a person who has had prior scabies, symptoms usually appear much sooner (1 to 4 days) after exposure. An infested person can spread scabies during the asymptomatic phase.
- Persons are communicable with scabies until the mites and eggs are destroyed by treatment, typically after 1 course of a topical scabicide treatment or, sometimes, 2 courses one week apart. Concurrent disinfestation of clothing and bedding via hot laundering is also indicated.
- Prophylactic (preventive) treatment may be appropriate for the dental hygienist who has been in contact with a patient/client with scabies. A primary care provider (e.g., physician or nurse practitioner) should be consulted.
- Avoid direct contact with infested skin and infested clothing/bedding.
- If you, the dental hygienist, have scabies, you should be treated with a prescription scabicide. In general, a healthcare provider whose role involves close contact with patients/clients can return to work once treatment is begun (i.e., at least 8 hours after the application of a topical scabicide; usually this is specified as the day after treatment). Itching may persist for 1 to 2 weeks; this should not be regarded as a sign of treatment failure or re-infestation. The local public health unit can be further consulted regarding any workplace restrictions, particularly in the case of Norwegian scabies.
- None internal in the mouth. However, scratching may result in secondary local infection such as perioral impetigo or cellulitis.
- Head and neck involvement is rare in adults, but common in infants.
Related signs and symptoms
- Scabies is a parasitic infection of the skin caused by a microscopic mite, which burrows into the upper layer of the skin to live and lay eggs. The skin penetration is visible as vesicles, papules, and/or linear burrows. In men, visible lesions are typically found in the finger webs, anterior surfaces of wrists and elbows, anterior axillary folds, belt line, thighs and external genitalia. In women, lesions tend to be prominent around the nipples and on the abdomen and lower buttocks. In infants and young children, the head, neck, palms and soles may be involved — sites that are unusual in adults and older children.
- When a person is infested with scabies mites for the first time, symptoms typically take 4 to 8 weeks to manifest. An infested person, however, can transmit scabies even if he/she doesn’t have symptoms.
- Scabies is usually characterized by severe itching (pruritus), particularly at night. However, in some immunocompromised, elderly, disabled, or debilitated patients/clients, infestation may appear as a generalized dermatitis, with extensive scaling and crusting and sometimes vesiculation (“Norwegian scabies”), and the itching may be reduced or absent. Persons with Norwegian scabies are highly contagious to others, and they should receive prompt treatment to prevent outbreaks.
- Complications are a result of lesions secondarily infected by scratching. These include impetigo, cellulitis, and, more rarely, kidney damage (acute and post-streptococcal glomerulonephritis).
- Scabies occurs worldwide and affects persons of all social classes. Scabies can spread rapidly in crowded conditions where close body contact is common. Institutional outbreaks tend to occur in nursing homes, extended-care facilities, and prisons. Childcare facilities also are a frequent site of scabies infestations.
References and sources of more detailed information
- Hamilton Public Health Services, Health Protection Division
- Centers for Disease Control and Prevention
- Mayo Clinic
- Heymann DL (ed.). Control of Communicable Disease Manual (20th edition). Washington: American Public Health Association; 2015.
Date: June 1, 2014
Revised: April 29, 2020