Head lice

1. Head lice Key Slides

2. Diagnosis and treatmentClinical Knowledge Summaries November 2007; Head Louse Stafford Report 2008Department of Health Patient Information Leaflet 2007 DH0077269 Confirm presence of live, moving lice Detect using wet or dry combing More reliable than direct visual inspection, but can be time– consuming Eggs alone are not diagnostic as the shells may be empty Check heads of family members and contacts Itching (due to louse faeces/saliva) can take up to 12 weeks to appear All affected individuals should be treated simultaneously Recommended options: Insecticide (carbaryl, malathion, phenothrin) Dimeticone Eradication combing (bug busting) Choice depends on patient/parent preference and treatment history

3. InsecticidesClinical Knowledge Summaries November 2007 Three classes of insecticide: Organophosphate = malathion Pyrethroids = phenothrin, permethrin Carbamate = carbaryl Some preparations unsuitable as they are not in contact with the lice for sufficient time eg crème rinse, mousse, shampoos Aqueous malathion or phenothrin (0.5%) recommended first line Local policy may differ if local resistance patterns are known Alcoholic products are flammable and can irritate the skin and have no evidence of greater efficacy than aqueous products Avoid in pregnancy and breastfeeding Malathion recommended in pregnancy if an insecticide is thought to be necessary Apply to dry hair from roots to tips Leave on for 12 hours or overnight before rinsing off Repeat after 7 days

4. Not an insecticide Creates physical barrier around louse May affect ability of lice to manage water balance Little effect on eggs Physical action rather than chemical so activity should be maintained in insecticide-resistant lice Apply to dry hair from roots to tips and leave on for 8 hours or overnight before washing off Must fully cover hair Requires repeat application after 7 days information contained in patient leaflet Longer term assessment needed to determine effectiveness compared to other treatments Suitable for use in pregnancy/breastfeeding Dimeticone Clinical Knowledge Summaries November 2007; Head Louse Stafford Report 2008

5. Mechanical removal (bug busting) Clinical Knowledge Summaries November 2007; Head Louse Stafford Report 2008 Similar method to wet detection combing Essential that technique is carried out appropriately and thoroughly to be effective Labour intensive (each session takes about 30 minutes) Requires high level of commitment Four sessions over 2 weeks Continue until no full-grown lice have been seen for three consecutive sessions Correct equipment needed Comb with teeth spaced <0.3mm apart

6. Other treatmentsClinical Knowledge Summaries November 2007; Head Louse Stafford Report 2008 Little or no evidence of effectiveness: Herbal and essential oils Some essential oils such as tea tree oil and lavender oil can be quite toxic, especially as concentrates Electronic combs Vinegar, mayonnaise, isopropyl alcohol, melted butter, petroleum jelly found to be ineffective

7. Confirming success or failureClinical Knowledge Summaries November 2007; Head Louse Stafford Report 2008 Perform the first detection combing 2–3 days after second application Insecticide resistance is likely if both adult lice and nymphs are found and the prescriber is certain that the insecticide product has been used correctly If no lice or nymphs are found in the first session, repeat detection combing 8–10 days after treatment. Have any viable eggs survived initial treatment? Were any lice missed in the previous session of detection combing (ie indicating treatment ineffective)? Has re–infestation occurred? Successful eradication of head lice is confirmed when no head lice or nymphs are found in both detection combing sessions

8. Treatment failureClinical Knowledge Summaries November 2007; Head Louse Stafford Report 2008 First, confirm if moving louse has been found Possible reasons for treatment failure include: Insufficient application or incorrect technique Repeat treatment with correct amount lotion/ type of comb or use alternative approach Resistance to insecticide Consider different class of insecticide or different treatment approach Reinfestation via untreated contact Detection combing of contacts Treat contacts simultaneously

9. Prevention of infestationClinical Knowledge Summaries November 2007; Head Louse Stafford Report 2008 No specific agents recommended Do not use insecticides to prevent infestation Repellents not recommended Regular detection combing won’t prevent infestation but may aid earlier detection Transmission controlled by contact tracing, detection combing, treating positive cases simultaneously

10. Three steps to head louse heaven • Treat only if infestation is confirmed • Use detection combing • Requires the presence of a live, moving louse • Don’t treat just in case • Use an effective treatment and do it properly • Choice depends on preference of parent/patient • Malathion or phenothrin 0.5% aqueous solution, dimeticone 4% solution, or wet combing • All need repeat treatment: ensure instructions are clear • Check success and consider all possibilities before deciding what to do next (poor technique, re-infestation as well as insecticide resistance) • Repellents are not recommended but frequent detection combing will allow prompt treatment