The following recommendations are largely based on guidance from NICE CKS (updated May 2024) and the British Association of Dermatologists (BAD, October 2023).

Scabies is an intensely itchy skin infestation, which is characteristically worse at night, caused by the human parasite Sarcoptes scabiei, a mite that burrows into the epidermis and tunnels through the stratum corneum. The life cycle lasts for 4–6 weeks. The female lays about 25 eggs, then dies. The eggs develop into adults in 10–15 days.

The trunk and limbs are the predominant sites that are affected. The face and scalp are rarely involved other than in infants and bed-bound elderly patients.

Classical scabies (typical scabies) involves infestation with a low number of mites (about 5–15 per host).

Crusted scabies is a hyper-infestation with thousands or millions of mites present in exfoliating scales of skin. It develops as a result of an insufficient immune response by the host.

Additional information for patients is available from MyHealth Devon.

Transmission

People with scabies should be informed about its transmission through skin-to-skin contact, particularly between sexual partners and people living in the same household, and secondarily by fomite transmission.

It could also include any other skin contacts such as members of sports teams and individuals who do not live in an affected household but provide care, e.g. visiting family members, child minders, and adult day care providers. Not all individuals with scabies have itch and rash. Asymptomatic people will re-infest their contacts if they are not treated concurrently.

Classical scabies is transmitted through close/prolonged skin contact with an infected person. The mites can live away from a host for an average of 24–36 hours.

Crusted scabies is highly contagious, and, in addition to transmission by direct contact, is easily transmissible via bedding, towels, clothes, and upholstery due to the large numbers of mites on an infested person. The mites can survive away from the host for up to 7 days. In the event of cases or outbreaks of crusted scabies, a higher index of suspicion of transmission via more transient contacts may be warranted.

Hygiene measures to reduce transmission

The risk of transmission can be reduced by limiting the number of sexual partners and observing strict personal hygiene when living in crowded spaces (e.g. no sharing of underwear clothing, bedding and towels and avoidance of skin-to-skin contact). Transmission is not prevented by condom use.

All clothes, soft slippers, towels and bed linen of the affected case should be decontaminated by washing at a high temperature (at least 60°C) on the day of application of the first treatment. If clothes cannot be washed at high temperature, they can be sealed in plastic bags for 4 days at room temperature, after which mites are unlikely to survive.

Alternative methods include pressing clothes with a warm iron, dry cleaning and putting items into a hot cycle in the dryer for 10 to 30 minutes.

Treatment

People with scabies should be offered screening for other sexually transmitted infections (STIs).

All members of their household, their sexual partners within the past month, and any other close personal contacts (even if asymptomatic) should also be treated at the same time as the index case.

For people with profuse and crusting scabies seek specialist advice. Admission to hospital may be required. People with crusted scabies should be isolated and barrier nursing procedures instituted. It may be necessary to investigate for underlying immunodeficiency.

Classical scabies

First line treatment is with a topical scabicide (unless contraindicated or not suitable):

Permethrin 5% cream

• Adults and children over 2 months: Apply once weekly for 2 doses, apply cream over whole body including face, neck, scalp, and ears then wash off after 8–12 hours. Repeat after 7 days.
  • If hands are washed with soap within 8 hours of application, they should be retreated.

OR

Malathion 0.5% cutaneous aqueous liquid

• Adults and children aged over 6 months: Apply once weekly for 2 doses, apply preparation over whole body, and wash off after 24 hours. Repeat after 7 days.
  • If hands are washed with soap within 24 hours of application, they should be retreated.

See section: 13.10.4 Parasiticidal preparations.

If topical therapy is contraindicated or not suitable, use oral ivermectin first line:

Ivermectin 3mg tablets

• Adults and children weighing at least 15kg: One dose (200micrograms/kg body weight) on day one; repeat the dose once after 7 days to kill recently hatched mites.
• Not for use in children under 15kg.
• No food should be taken within two hours before or after administration.
• See section: 13.10.4 Parasiticidal preparations.

Follow up

Itching may continue for up to 4 weeks after successful treatment of scabies. People should seek medical advice if itching persists for longer than 2-4 weeks after the last treatment application.

Post-scabietic itch

For post-scabietic itch, consider crotamiton 10% cream or, if the scabies mites have definitely been eradicated, topical hydrocortisone 1% (cream or ointment).

Night-time use of a sedating antihistamine (such as chlorphenamine) may help with sleep and reduce scratching.

See sections: 13.3 Antipruritics, 13.4 Topical corticosteroids, and 3.4.1 Antihistamines.

Treatment failure

Appearance of new burrows and/or evidence of visible mites at any stage beyond 7 days after completion of anti-scabies treatment (including repeat course) is indicative of need for further treatment.

If topical therapy has failed, consider retreatment with a further course of topical therapy, or one course of ivermectin (one dose [200micrograms/kg body weight] on day one, repeat the dose once after 7 days) (see above).

If one course (two doses) of oral ivermectin has failed, refer to specialist.

Closed setting outbreaks

These are defined as any setting where a number of people are living with close contact inside the setting (shared bathroom or communal areas) and often more limited contact with the wider community and includes the staff working within the setting.

Examples (not exhaustive) of closed settings include:

• care homes
• prisons
• long-term hotel or hostel accommodation
• homeless hostels.

Before initiating treatment of single cases, all residents and staff should be checked for symptoms and signs of scabies. Assessing clinicians should be aware of the potential for asymptomatic infection, particularly in the elderly.

Oral ivermectin is a recognised treatment for scabies within closed settings, when there are logistical considerations in the successful delivery of topical therapy, or in the context of immunosuppression or crusted scabies.

For further information on the management of scabies cases in closed settings, please refer to the UKHSA guidance, here.

Referral

Refer patients to a specialist if one course (2 doses) of oral ivermectin have failed or there is diagnostic uncertainty.

For people with persistent nodular scabies, refer to a dermatologist. Treatment with high-potency topical steroids, intralesional steroids, oral steroids, or oral ivermectin may be required.