• Lice: parasitic insects that survive by feeding on human blood and can be found on peoples heads and bodies, including the pubic area. 3 types of lice that live on humans:

  • Pediculus humanus capitis (head louse)

  • Pediculus humanus corporis (body louse, clothes louse)

  • Pthirus pubis ("crab" / pubic louse)

• Head lice: Most common in children aged 4-11. Most acquired by direct head-to-head contact. Can be asymptomatic or cause scalp pruritus. Diagnosis of active infection made if a live head louse if found (comb wet or dry hair with a detection comb). Lice are up to 3mm long, are grey-white to black in colour, and have 6 legs. Louse eggs (ova or nits) are small, yellow-white and attached to hair shafts (usually take 7-10 days to hatch). Can get secondary scalp infection (scalp impetigo) as result of scratching. Severe cases can lead to matting of the hair. Insecticide treatment options (refer to local guidelines as there is resistance to malathion and pyrethroid in the UK)

  • Dimeticone 4% lotion (Hedrin lotion): left on hair scalp for 8 hours (or overnight) then washed out and repeated after 7 days

  • Malathion 0.5% aqueous liquid: left on hair scalp for 12 hours (or overnight) then washed out and repeated after 7 days

  • Coconet, anise and yiang yiang spray (Lyclear Spray Away)

  • Isopropyl myristate and cyclomethicone (Full Marks solution)

• Wet combing: alternative to use of chemical agents (probably less effective). Combing wet hair with Bug Buster comb for 4 sessions over 2 weeks

• Pregnant or breast-feeding: treat with wet combing or dimeticone lotion

• Public lice: STI screening if acquired via sexual contact. Treat with topical insecticide: 2 applications of malathion 0.5% aqueous lotion or Permethrin 5% dermal cream, 7 days apart

• Resources: Lice (CDC), Head lice (CKS), Head lice - syn. pediculosis capitus (PCDS), Lice and scabies treatments (MIMS), Pubic lice (CKS), Pubic lice (NHS Choices)

Scabies

• Mite infection. Skin-to-skin transmission. Itch - typically worse at night. Mainly affects limbs and trunk. Generalised rash with erythema, papular and urticated lesions (caused by allergy to the mites). Burrows (very small irregular tracks) seen on sides of fingers, wrists, feet, groins, axillae, genitalia. Secondary infection with impetigo common.

• Crusted scabies (Norwegian scabies): Generalised scaly rash (itch less common). Highly contagious. Occurs in patients with dementia, Down's syndrome, immunosupression, excessive topical steroid use

• Permethrin 5% cream (Lyclear) (first-line) (1 x 30g tube should cover an average adult) repeated after 7 days; Malathion 0.5% lotion (second-line); Eurax HC for itch which may not resolve for at least 1 month

RedWhale take home messages:

• It’s usually a clinical diagnosis based on history of itch and/or typical rash – you don’t HAVE to see a mite or do skin scrapings.

• Look in webs of fingers/toes, sides of hands and feet, the belt line, nipples and buttocks.

• Permethrin 5% cream is the first-line treatment (malathion 0.5% is an alternative).

• Make sure the person knows how to use the permethrin (click the full Pearl for details).

• Treat the whole body, the whole household and close contacts all at the same time. Repeat 7d later.

• Outbreaks in closed settings need special consideration. The UKHSA can support.

Resources

• Scabies (CKS). Scabies (NHS Choices), Scabies (PCDS)