Scabies

• Caused by an infestation with a tiny parasitic mite which burrows underneath and lives in the skin
• Itching and scratching cause sores that can get infected with bacteria and lead to kidney and rheumatic heart problems or sepsis
• Spread by direct skin to skin contact — mites can only live 2–3 days off the body
• To stop spread you must treat person and all close contacts including family and household

Ask

• Itching, scratching
• Rash — hidden by clothing or on private part
• Other family members with scabies
• Anyone in family or community with crusted scabies — possible source of infection
• Always consider this for children or elderly people with frequent presentations

Check

Do

• If infected sores — treat as for impetigo (school sores) at same time as treating scabies 

Do — treat with topical permethrin 5% OR oral ivermectin

• Tell person itching may last for 1–4 weeks after treatment with permethrin or ivermectin
• ALSO treat all household members, close contacts and people who have had close physical contact (eg person holding child with scabies) with permethrin 5% cream

For topical permethrin 5% cream

• In clinic demonstrate whole-body application of thin layer
• Adults and children — leave on for at least 8 hours. Best overnight under clean bed clothes
• Babies under 6 months — leave on for 6–8 hours
• Repeat treatment in 1 week to kill any new mites that hatch after first application

Applying scabies creams or lotions

• Put on clean, dry skin — best at night before bed and left on for at least 8 hours under clean pyjamas or clothes 
• Apply to whole body including scalp and face and behind ears — avoid eyes, lips, mouth. 
• If hair very thick or infestation very bad — may need to shave head. Always get permission from person/carer
• Work carefully down whole body. Always include between fingers and toes, soles of feet, under nails AND body creases — behind ears, under jaw, neck, armpits, back, bottom, groin, under breasts AND joints and joints creases — elbows, knees, heels
• Advise to put cream on hands again after washing and put on child’s hands again before bed

For ivermectin — give oral single dose with food (doses)

• Do not give to children under 5 years or less than 15kg OR women who are or could be pregnant or are breastfeeding — do urine pregnancy test if not sure or no contraception
• Repeat in 7–14 days to kill any new mites that hatch

Prevention

• Encourage hand washing and short finger nails
• Ask family to wash clothes and sheets with laundry detergent and dry in sun and to air blankets and mattresses in full sun
• Bed linen and sheets, towels and clothes that cannot be washed can be decontaminated by placing in a sealed plastic bag for at least 8 days — scabies eggs will hatch mites which will die
• Home visit to look for and treat other people with scabies or crusted scabies — may be source of infection

Do — if difficult case or treatment failure

• 2 or more presentations of scabies where
•  Permethrin 5% cream application or oral ivermectin has not worked
• AND reinfection unlikely because child treated properly/in clinic, repeat application of cream applied or repeat dose of ivermectin has been given and all contacts treated
• If severe scabies affecting a lot of skin and person sick — medical consult

Step 1

Whole-body application of benzyl benzoate 25% lotion — see applying scabies creams and lotions 

• Child under 6 months — do not use
• Child 6–23 months — dilute with 3 parts water
• Child 2–12 years and adults with sensitive skin — dilute with equal part water
• Occasionally causes severe skin irritation — usually resolves in 15 minutes
• Test on small area of skin first — wait for 10 minutes
• If severe reaction — dilute with equal part water for adults. Do not use for children
• Leave on for 24 hours

Step 2

Repeat topical treatment in 1 week — whole body application of benzyl benzoate 25% lotion as in Step 1

Follow-up

• Make sure second dose of treatment has been given
• After 7 days for topical permethrin 5% cream or benzyl benzoate lotion — applied in clinic if required
• After 7–14 days for oral ivermectin 
• Return to clinic 3 weeks after second dose of treatment completed to check response
• If person has scabies often — consider
• Was cream/lotion applied properly
• Did whole family/household get treated
• Did everyone get second treatment 
• Is there someone with crusted scabies
• Is it hard to maintain good hygiene at home — washing facilities and household cleaning
• Less common skin conditions that need review
• Make sure anyone in community with crusted scabies gets treatment as a high priority — unless they are treated, contacts will keep getting scabies
• If a lot of scabies in community — consider community healthy skin program
• Where prevalence of scabies is assessed as 10% or higher consider an ivermectin-based mass drug administration (MDA) program
• Talk with primary care team,  PHU  and infectious disease specialist 

Crusted scabies

• Severe type of scabies caused by same mite — not sores from infected scabies. Person’s immune system can’t control number of mites, so thousands of mites and very infectious
• High risk of serious bacterial infection in more severe cases. Lifelong risk of recurrence, reduced life expectancy — manage as a chronic conditions
• Can involve 'shame' and social isolation — take care to be culturally sensitive

Check

• Look for thickened, scaly skin patches — may be 1–2 areas (eg bottom, hands, feet, shoulders) or may cover whole body with thick/flaky crust
• Scale may have distinctive creamy colour, even in dark skinned people
• Can look like tinea, psoriasis, eczema, dermatitis, impetigo (school sores) with a crust
• Often not itchy

Do not

• Do not confuse crusted scabies with severe scabies (with or without crusted skin sores) or tinea

Do

For each episode

• Blood for FBC, UEC, LFT, CRP, HbA1c and blood cultures
• Skin scrapings — scabies microscopy, fungal culture. Use to confirm diagnosis and for notification to PHU
• If associated with impetigo (school sores) — collect swab for MC&S
• If associated with nail disease — collect nail clippings for fungal growth

Diagnosis 

• If crusted scabies suspected — urgent medical consult as soon as possible
• Can be difficult to diagnosis — must discuss with specialist
• Must notify confirmed cases — based on laboratory finding of scabies mites on scraping AND infectious disease specialist or dermatologist consult of in person, via photos (with consent) or videoconference
• May consider if not done previously — blood for HIV (repeat if ongoing risk), HTLV-1, ANA,  IgE/immunoglobulin, T-cell subsets
• If ANA positive take blood for dsDNA, ENA, C3, C4

Always talk with PHU or infectious diseases specialist

• Confirmed cases get public health response via clinic with contact tracing and treatment of household and close contacts
• Most people with crusted scabies need to be sent to hospital
• People with Grade 2 or Grade 3 always send to hospital
• Some people with mild Grade 1 can be managed in community in consult with infectious diseases unit or specialist scabies service

Grade severity

• Choose best option in each category and add numbers to get score — Table 7.32
• Assessment should always be made in consultation with PHU/infectious diseases specialist

A — Distribution and extent of crusting

1. Wrists, web spaces, feet only — less than 10% of total body surface area (TBSA)
2. As above PLUS forearms, lower legs, buttocks, trunk OR 10–30% TBSA
3. As above PLUS scalp OR more than 30% TBSA

B — Crusting/shedding

1. Mild crusting (less than 5mm deep), minimal skin shedding
2. Moderate crusting (5–10mm deep), moderate skin shedding
3. Severe crusting (more than 10mm deep), profuse skin shedding

C — Past episodes

1. Never had it before
2. Already been in hospital 1–3 times for crusted scabies OR depigmentation of elbows, knees
3. Already been in hospital 4 or more times for crusted scabies OR depigmentation of elbows, knees, legs/back OR residual skin thickening or scaly skin

D — Skin conditions

1. No cracking or pyoderma (pus in skin)
2. Any of — multiple pustules, weeping sores, superficial skin cracking
3. Deep skin cracking with bleeding, widespread purulent exudates (pussy fluids)

Score of grade severity

Do not

Do not treat patients with Grade 2 or 3 crusted scabies in the community — for all suspected cases talk with PHU/infectious diseases specialist

Do — Grade 1 infection only

Can trial community management in consult with infectious diseases unit or specialist scabies service. Frequent clinical supervision needed — best with directly observed therapy (DOT)

• Give ivermectin oral once a day on days 0, 1, 7 — doses
• Do not give to children under 5 years or less than 15kg OR women who are or could be pregnant or are breastfeeding — do urine pregnancy test if not sure or no contraception 
• Whole-body application of topical agent — see applying scabies creams or lotions
• Put on dry skin after soaking and scrubbing skin in bath or shower
• Apply every second day for first week THEN twice a week until cured
• Benzyl benzoate 25% lotion
• Child under 6 months — do not use
• Child 6–23 months — dilute with 3 parts water
• Child 2–12 years and sensitive adults — dilute with equal parts water
• Occasionally causes severe skin irritation — usually resolves in 15 minutes
• Test on small area of skin first — leave for 10 minutes
• If severe reaction — dilute with equal part water for adults. Do not use for children
• Leave on for 24 hours
• OR permethrin 5% cream — if benzyl benzoate not available or not tolerated
• Leave on for at least 8 hours (overnight)
• Use lactic acid and urea cream every second day to soften skin — use on different day to scabies cream

Treating family and house

• Aim to make household a ‘scabies-free zone’ to protect person from reinfection after treatment
• Educate person and family about what this means, includes treatment for visitors so person who gets crusted scabies can avoid reinfection
• Treat all household members, family and close contacts for scabies with permethrin 5% cream
• Work with hospital to ensure person not discharged home before all contracts treated
• Ask family to make sure that while having treatment with topical permethrin cream or oral ivermectin they
  
• Wash underwear, bed clothes, towels and bed linen on hot 60*C wash cycle
• Take mattresses, blankets and doonas outside or hang on the washing line in full sunlight for 72 hours
• Vacuum and sweep floor and soft furnishings to remove skin particles
• Sensitive management of household is needed due to stigma and chronic nature of disease

Long-term follow-up of crusted scabies

Secondary prevention
For people getting recurrent crusted scabies or with high risk of re-exposure, eg living in house with young children

• Give supervised whole-body application of topical treatment preferably with benzyl benzoate lotion — every 2–4 weeks for 6 months THEN review
• If reinfection — infectious disease specialist consult about management
• Treat early before crusts form

Review

• At 2 weeks and 4 weeks after discharge THEN every 4 weeks to check skin for signs of reinfection — especially hands, shoulders, bottom
• Moisturise daily to keep skin soft, eg sorbolene
• Regular reviews and early treatment if reinfected — important to break cycle of scabies transmission and community outbreaks
• Lifelong follow-up is needed while living in scabies endemic area

Develop chronic care management plan

• High risk of reinfection
• Need good communication between acute and primary care providers
• Provide ongoing education — important that person and family understand
• About crusted scabies
• What they can do to self-manage
• Importance of a 'scabies-free zone'