Strength of recommendations (A, B, C, D, I) and quality of evidence (good, fair, poor) are defined at the end of "Major Recommendations" field.
Diagnosis
- Finding a live louse or nymph on the scalp or a viable egg within 1cm of the scalp (Elston, 2005; Mumcuoglu et al., 2006; Roberts & Burgess, 2005)
- Nits that are within 6 mm from the scalp are usually viable and are highly suggestive of an active infestation (Ko & Elston, 2004; Leung, Fong, & Pinto-Rojas, 2005).
- Nits that are more than 1cm from the scalp are generally not viable (Leung, Fong, & Pinto-Rojas, 2005).
- Using a light source, a magnifying lens and parting the hair at the scalp may aid in detection (Sciscione & Krause-Parello, 2007).
- Lice eggs or nits may be easier to detect, especially behind the ears or at the nape of the neck
- Using a fine-tooth louse comb is 4 times more efficient than direct visual examination and twice as fast (Elston, 2005; Mumcuoglu et al, 2006).
Evidence Good, Recommendation A
Recommended Regimens
- 1% Permethrin is treatment of choice because of efficacy and lack of toxicity (Burkhart, 2004; Burkhart & Burkhart, 2006; Downs, 2004; Elston, 2005; Hansen, 2004; Ko & Elston, 2004; Lebwohl, Clark, & Levitt, 2007; Leung, Fong, & Pinto-Rojas, 2005).
- 1% Permethrin cream rinse is applied to the hair and scalp for 10 minutes and then rinsed off.
- A second treatment is advised 7 to 10 days later to ensure cure.
Evidence Good, Recommendation B
- Pyrethrin 0.33% and piperonyl butoxide 4% (Burkhart, 2004; Burkhart & Burkhart, 2006; Elston, 2005; Hansen, 2004; Ko & Elston, 2004; Lebwohl, Clark, & Levitt, 2007; Leung, Fong, & Pinto-Rojas, 2005).
- Product is applied to hair that is first shampooed and then towel dried, left on for 10 minutes, and then rinsed off.
- These agents are not ovicidal and application should be repeated 7 days later to ensure cure.
Evidence Good, Recommendation B
- 0.5% Malathion lotion (Burkhart, 2004; Burkhart & Burkhart, 2006; Downs, 2004; Elston, 2005; Hansen, 2004; Ko & Elston, 2004; Lebwohl, Clark, & Levitt, 2007; Leung, Fong, & Pinto-Rojas, 2005; Meinking et al., 2007; West, 2004).
- The lotion is applied to the hair until thoroughly moistened, left to air dry, and then rinsed off after 8 to 12 hours.
- A drawback to its use is its lengthy application time (Meinking et al., 2007).
- Some authors report success with 0.5% malathion gel formulation, which only requires a 30-minute application time (Meinking et al., 2007).
- The application should be repeated in 7 to 9 days if live lice are still present at that time.
- Safety and efficacy have not been established in children less than 6 years of age.
- Preferred first line treatment in regions where pyrethroid resistance has been observed.
Evidence Good, Recommendation B
Alternative Regimens
- Combing of wet hair using a conditioner of choice and a fine-tooth louse comb (Downs, 2004; Elston, 2005; Ibarra et al., 2007; Ko & Elston, 2004; Lebwohl, Clark, & Levitt, 2007; Mumcuoglu et al., 2007; Tebruegge & Runnacles, 2007).
- Wet combing is treatment of choice for children younger than 2 years of age (Leung, Fong, & Pinto-Rojas, 2005).
- Repeat combing needs to be done over 2 weeks on days 1, 5, 9, and 13 to break the life-cycle (Ibarra et al., 2007).
- Because no pediculicide is 100% ovicidal, removal of nits by wet combing is recommended by some authors (Leung, Fong, & Pinto-Rojas, 2005).
Evidence Good, Recommendation C
- Ivermectin 200 micrograms/kilogram orally (PO) with a repeat dose 2 weeks later (Burkhart, 2004; Burkhart & Burkhart, 2006; Elston, 2005; Dourmishev, Dourmishev, & Schwartz, 2005; Downs, 2004; Ko & Elston, 2004; Lebwohl, Clark, & Levitt, 2007; West, 2004).
- Topical ivermectin holds some promise for the treatment of head lice, but oral ivermectin is the only form licensed for human use in the United States.
Evidence Fair, Recommendation C
- A combination of 1% permethrin and/or trimethoprim 10 mg/kg/day and sulfamethoxazole 50 mg/kg/day in 2 divided doses for 10 days (Ko & Elston, 2004; Lebwohl, Clark, & Levitt, 2007; Leung, Fong, & Pinto-Rojas, 2005).
- Should only be reserved for cases not responsive to traditional pediculicides or suspected cases of lice-related resistance to therapy.
Evidence Fair, Recommendation C
- Lindane shampoo 1% (60 mL) (Burkhart, 2004; Downs, 2004; Elston, 2005; Ko & Elston, 2004; Lebwohl, Clark, & Levitt, 2007; Leung, Fong, & Pinto-Rojas, 2005; West, 2004).
- Should be used only in patients who cannot tolerate first-line treatment, or in whom first-line treatment with safer products has failed (Burkhart, 2004; Hansen, 2004).
- Wash hair with regular shampoo at least 1 hour before applying lindane and dry thoroughly. Do not use any creams, oils, or conditioners.
- Shake the shampoo well. Apply just enough shampoo to make hair and scalp wet.
- Throw away any remaining shampoo.
- Leave the lindane shampoo on hair for exactly 4 minutes. Longer exposure times may cause seizures or other serious problems. Keep hair uncovered during this time.
- At the end of 4 minutes, use a small amount of warm water to lather the shampoo. Do not use hot water.
- Wash all of the shampoo off of hair and skin with warm water.
- Dry hair with a clean towel.
- Comb hair with a fine tooth comb (nit comb) or use tweezers to remove nits (lice eggs and larvae).
- Should not be reapplied if initial treatment fails (Burkhart, 2004).
Evidence Good, Recommendation D
Other Management Considerations
- Family members should be treated only if infected (Elewski, 2005; Lebwohl, Clark, & Levitt, 2007; Leung, Fong, & Pinto-Rojas, 2005).
- Personal hair care items should be treated with pediculocides or soaked in hot water (Ko & Elston, 2004; Leung, Fong, & Pinto-Rojas, 2005).
- Bedding should be laundered in hot water of at least 50 degrees Celsius and tumble dried on the hot cycle for 40 minutes, or dry cleaned within 48 hours of contact of head of an infested person (Izri & Chosidow, 2006; Ko & Elston, 2004).
- Schools or child care facilities should be notified so that additional cases can be detected and treated (Ko & Elston, 2004; Lebwohl, Clark, & Levitt, 2007; Mumcuoglu et al., 2007; Sciscione, 2007).
- Resistance to pediculocides has been detected in some areas of the country. Consider resistance in your area when determining treatment (Hansen, 2004; Mumcuoglu et al., 2007).
- Towel dry hair before using treatment as too much water in the hair dilutes the pediculicide, decreasing its efficacy.
- Do not use a cream rinse or conditioner shampoo before using the treatment as it will interfere with the medication.
- Do not wash hair for 1 to 2 days after treatment.
- Long hair may require more than 1 bottle of product per treatment. In most cases, 50 mL of product is required for each application. In those patients with long or thick hair, up to 150 mL may be required.
Evidence Fair, Recommendation C
Follow-Up
- If infestation persists after 2 treatments consider evaluating for correct use of product and an alternative agent should be used (Hansen, 2004).
- Causes of treatment failure in head lice infestations include misdiagnosis, noncompliance or not following product instructions, reinfestation, or resistance of lice to the pediculocide.
Evidence Good, Recommendation B
Special Considerations
- Children younger than 2 years of age
- Wet combing is the only treatment recommended for children younger than 2 years (Leung, Fong, & Pinto-Rojas, 2005).
Evidence Good, Recommendation A
- Pregnancy
- Permethrin, pyrethrin, and malathion are category 'B' drugs.
Evidence Good, Recommendation A
Definitions:
Quality of Evidence (Based on U.S. Preventive Services Task Force [USPSTF] Ratings)
Good: Evidence includes consistent results from well-designed, well-conducted studies in representative populations that directly assess effects on health outcomes.
Fair: Evidence is sufficient to determine effects on health outcomes, but the strength of the evidence is limited by the number, quality, or consistency of the individual studies, generalizability to routine practice, or indirect nature of the evidence of health outcomes.
Poor: Evidence is insufficient to assess the effects on health outcomes because of limited number of power of studies, important flaws in their designs or conduct, gaps in the chain of evidence, or lack of information on important health outcomes.
Grading of Recommendations (Based on USPSTF Ratings)
A. There is good evidence that the recommendation improves important health outcomes. Benefits substantially outweigh harms.
B. There is at least fair evidence that the recommendation improves important health outcomes. Benefits outweigh harms.
C. There is at least fair evidence that the service can improve health outcomes but the balance of benefits and harms is too close to justify a general recommendation.
D. There is at least fair evidence that the recommendation is ineffective or that harms outweigh benefits.
I. Evidence that the service is effective is lacking, of poor quality or conflicting and the balance of benefits and harms cannot be determined.
