What is the treatment for pubic lice (crabs)?

Treatment for Pubic Lice (Crabs)

The first-line treatment for pubic lice (crabs) is permethrin 1% cream rinse applied to affected areas and washed off after 10 minutes, or pyrethrins with piperonyl butoxide applied similarly. 1

First-Line Treatment Options

• Permethrin 1% cream rinse: Apply to affected areas, wash off after 10 minutes
• Pyrethrins with piperonyl butoxide: Apply to affected areas, wash off after 10 minutes

These treatments are effective and have a good safety profile. Permethrin has less potential for toxicity than other options like lindane 1.

Alternative Treatment Options (if first-line fails)

• Malathion 0.5% lotion: Apply to affected areas, wash off after 8-12 hours
• Ivermectin: 250μg/kg orally, repeated in 2 weeks

Resistance to permethrin and pyrethrins has been increasing 1, so alternative treatments may be necessary if initial treatment fails.

Special Considerations

Eyelash Infestation

• Do not apply pediculicides to the eyes
• For eyelash infestation, apply occlusive ophthalmic ointment to eyelid margins twice daily for 10 days 1

Pregnancy and Lactation

• Pregnant and lactating women should use permethrin or pyrethrins with piperonyl butoxide 1
• Avoid lindane in pregnant women due to association with neural tube defects 1

Children

• Lindane should not be used in children under 10 years of age 1

Additional Management Steps

1. Decontaminate bedding and clothing:

   • Machine wash and dry using hot cycle, dry clean, or
   • Remove from body contact for at least 72 hours 1

2. Treat sexual partners:

   • All sexual partners from the previous month should be treated 1
   • Avoid sexual contact until both patient and partners are treated

3. Screen for other STIs:

   • Patients with pubic lice should be evaluated for other sexually transmitted infections 1

4. Follow-up:

   • Evaluate after 1 week if symptoms persist
   • Re-treatment may be necessary if live lice or eggs at hair-skin junction are found
   • If treatment fails, use an alternative regimen 1

Common Pitfalls to Avoid

1. Inadequate application: Ensure complete coverage of all affected areas
2. Failure to treat sexual partners: This can lead to reinfection
3. Improper use of lindane: Never use after bathing or on patients with extensive dermatitis
4. Incomplete environmental decontamination: Ensure all potentially contaminated items are properly treated
5. Mistaking nits for active infestation: The presence of nits alone doesn't necessarily indicate active infestation 2
6. Resistance issues: Be aware that resistance to pyrethrins has been reported 3, so follow-up is important

Remember that while pubic lice don't carry the same long-term health consequences as some other STIs, they are among the most commonly reported sexually transmitted conditions 4 and require proper treatment to prevent spread and relieve symptoms.