Head lice infestations Flashcards
Name for head lice?
pediculus humanus capitis
What is a lice infestation?
< 10 live lice
Transmission of lice?
direct head to head contact
Head lice or nits do not survive for long away from the scalp
Diagnosis of lice?
Detection of living louse by microscopy
Detecting nits alone doesn’t indicate active infestation
How long can you be asymptomatic from lice?
4-6 weeks (takes this long for sensitization to saliva_)
How do you treat lice?
Topical head lice insecticide
2 applications 7-10 days apart
- children >= 2 months: permethrin and pyethrins
- > = 2 years: dimethicone
- > = 4 years: myristate/ST-cyclomethicone
- > = 6 months: benzoyl alcohol lotion but is comparatively expensive
- Lindane no longer considered acceptable due to potential risk for neurotoxicity and bone marrow suppression (probable carcinogen)
What do you do when there is evidence of treatment failure (Detection of live lice)?
use a full course of topical treatment from a different class of medication
- rule out the following before considering resistance:
- misdiagnosis or over diagnosis (true diagnosis needs live lice)
- reinfestation after a previous treatment
- scalp may be itchy after applying a topical insecticide but itching doesn’t indicate treatment resistance or reinfestation
When can children with lice go back to school?
Now
- excluding children with nits or live lice from school or child care has no rational medical basis and isn’t recommended
Who is at risk of allergy to pyrethrins?
Allergy to ragweed
* note: true allergic reactions are rare
Permethrin does not cause allergic reactions
What is first line treatment for lice?
Permethrin (Kwellada) and Pyrethrins (R&C shampoo)
These are both insecticides
licensed for >= 2 mo
What are 2 noninsecticidal treatments for lice?
Isopropyl myristate/ST-cyclomethicone solution (Resultz)
- not recommended <4 yrs
Dimeticone solution
- not recommended <2 yrs
What treatment for lice is no longer recommended and why?
Lindane no longer considered acceptable due to potential risk for neurotoxicity and bone marrow suppression (probable carcinogen)
