Cause:Phthirus pubis; Pediculus corporis(body lice), P. capitis(head lice)

Pathophys:Attach to hair; itch and rashes due to bites and allergies to louse and its feces

P. pubis,venereal; P. corporisand P. capitis, via bedding, clothing, and other fomites

Life cycle: 25 d egg-to-egg. Live exclusively on human blood, can't live >24 h without it. Only ~10 adults/pt

Sx:Pruritus with all; P. pubislocalized to axillary, perianal, pubic areas, and occasionally in eyelashes (blepharitis)

Si:Lice and nits (egg sacks on hairs) evident w magnifying glass or careful inspection; bites

r/o bird lice (eg, from pigeons on air conditioner)

Rx:

(Med Let 1997;38:6)

Launder clothes, bedding; hang them outside × 24 h will also kill since can't survive >24 h away from body

Meds: rx as below, perhaps repeat × 1 at 7 d

• 1st:
• Permethrin 1% (Nix); $9/2 oz; 95% cure with 1 rx at 14 d (Am J Pub Hlth 1988;78:978), but resistance appearing
• 2nd:
• Permethrin 5% (Elimite) over night, 1st choice for pubic lice (Med Let 1999;41:89), avoid for head lice in children, or
• Malathion 0.5% (Ovide) (Med Let 1999;41:73) lotion × 8-12 h, then repeat in 1 wk, or
• Pyrethrins + piperonyl butoxide (Rid, Vonce, A-200, Pronto); 65% cure after 1 rx at 14 d (Am J Pub Hlth 1988;78:978); $5/2 oz
• 3rd:
• Lindane shampoos (1% gamma benzene hexachloride, Kwell), × 1 usually enough; may need × 3 q 4 d; $5/2 oz, or
• Ivermectin (Mectizan) 200 mgm/kg po or 400 µg/Kg on day 1 and 8; more effective than topical (Nejm 2010;362:896)
• 4th:
• Tm/S po bid × 10 d w permethrin topically (Peds 2001;107:575) improved cure from 80% to 95%

of eye cmplc: 0.25% eserine ophthalmic ointment to lids with cotton tip applicator

of school outbreaks, "nit-free policies unrealistic"