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Pediculosis: Treatment & Medication
Updated: May 5, 2009
- Overview
- Differential Diagnoses & Workup
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Treatment
Emergency Department Care
- Nits are best removed with a very fine comb.
- Soaking the hair in a solution of equal parts water and white vinegar and then wrapping the wet scalp in a towel for at least 15 minutes may facilitate removal.
- Treat all family members.
- Discard infested clothing or wash in very hot water.
- Evaluate for other STDs.
Medication
The goal of therapy is to eliminate lice and eggs.
Linen, clothing, and other materials may be treated with hot water washing.
Eyelash infestation can be treated effectively with petrolatum ointment (eg, Vaseline).
Pediculicides
Chemical pediculicides are the mainstay of therapy. Treatment should be repeated in 7-10 days (the time needed for the eggs to hatch) because nits are less effectively killed than adults.
All contacts should be treated simultaneously.
Resistance to pediculicides has increased over recent years. Therapeutic agents can be rotated to slow the emergence of resistance. Benzyl alcohol lotion is a new pediculicide that needs to be applied twice, but it might be an easier and safer alternative to lindane and malathion. With all treatments used to eliminate live lice, careful combing and removal of all nits from the hair as well as cleaning of other articles (ie, hair accessories, towels, bedding, clothing) are essential steps to prevent reinfestation.
The safety and effectiveness of benzyl alcohol lotion 5% was demonstrated in 2 multicenter, randomized, double-blind studies of 628 people, 6 months of age and older, with active head lice infestation. Individuals received two, 10-minute treatments of either benzyl alcohol lotion or topical placebo, 1 week apart. In these 2 studies, the drug was effective in eradicating lice in 76.2% and 75% of subjects compared with placebo 4.8% and 26.2%, respectively.5
Benzyl alcohol lotion
Benzyl alcohol inhibits lice from closing their respiratory spiracles, allowing the lotion to obstruct the spiracles, which ultimately results in asphyxiation. Does not elicit ovicidal activity. Contains 5% benzyl alcohol.
Adult
Apply lotion to dry hair, using enough to completely saturate scalp and hair; rinse off with water after 10 min; repeat treatment in 1 wk
Pediatric
<6 months: Do not use
>6 months: Apply as in adults
None reported
Documented hypersensitivity
Pregnancy
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Precautions
May cause irritation to skin, scalp, and eyes (avoid eye exposure and flush immediately with water if contact occurs); application site anesthesia and hypoesthesia may occur; serious adverse events (eg, respiratory distress, seizure, coma) and death with benzyl alcohol have been well documented in premature infants; IV administration of products containing benzyl alcohol has been associated with neonatal gasping syndrome consisting of severe metabolic acidosis, gasping respirations, progressive hypotension, seizures, CNS depression, intraventricular hemorrhage, and death in preterm, low birth weight infants; neonates (ie, <1 mo or preterm infants with a corrected age <44 wk) could be at risk for gasping syndrome if treated
Permethrin 5% (Elimite) or 1% (Nix) lotion
DOC, especially for infants >2 mo and small children. More effective than crotamiton in treating symptoms and reducing chances of secondary bacterial infection.
Even after successful treatment, postscabietic nodules and pruritus may persist for mo.
Adult
Apply topically to affected area; leave 5-10 min, then rinse
Pediatric
Administer as in adults
None reported
Documented hypersensitivity
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
May exacerbate redness, swelling, and itching, at least temporarily
Lindane 1% shampoo (Kwell)
Stimulates nervous system of parasite, causing seizures and death. Second-line treatment if other agents fail or are not tolerated. Not very safe in children due to transcutaneous absorption leading to neurotoxicity. Overall, permethrin is a safer choice.
Adult
Shampoo: Apply to dry head or pubic hair and surrounding areas; allow to set for 4 min, then lather for 4 min and rinse; repeat in 7 d prn
Pediatric
Administer as in adults
Oil-based hairdressings may increase toxicity of lindane
Documented hypersensitivity; neonates; acutely swollen skin or Norwegian scabies
Pregnancy
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Precautions
Caution if history of seizures; do not apply to eyes, face, or mucous membranes; penetrates human skin and may cause CNS toxicity in young children, seizures have occurred after inappropriate use or ingestion
Pyrethrin/Piperonyl butoxide shampoo (RID Mousse, RID Shampoo, A-200)
Treatment of P humanus infestations. Stimulates nervous system, causing seizures and death of parasite.
Adult
Apply shampoo to dry hair and allow to set for 10 min before rinsing; repeat in 1 wk prn
Pediatric
Administer as in adults
None reported
Documented hypersensitivity to product or Compositae plants
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Do not apply to eyes, face, or mucous membranes
Malathion (Ovide)
Approved by FDA to treat head lice. Irreversible cholinesterase inhibitor that is hydrolyzed and, therefore, detoxified rapidly by mammals but not by insects; ovicidal and pediculicidal. Binds to hair and provides some residual protection after therapy. Available as 0.5% and 1% aqueous-based lotions.
Adult
Apply lotion to dry hair; leave on 8-12 h, rinse; repeat in 7 d prn
Pediatric
<2 years: Not recommended
>2 years: Administer as in adults
None reported; however, potential for interaction with aminoglycosides and antimyasthenics
Documented hypersensitivity
Pregnancy
Precautions
Contains flammable alcohol; do not expose lotion or wet hair to open flame or electric heat, eg, hair dryers (allow hair to dry naturally and uncovered following application); avoid contact with eyes (flush eyes immediately with water if contact)
Ivermectin (Stromectol)
Binds selectively with glutamate-gated chloride ion channels in invertebrate nerve and muscle cells, causing cell death. Half-life is 16 h; metabolized in liver. DOC for onchocerciasis and strongyloidiasis. Recently shown to be effective against pediculosis but not yet approved by FDA. Not effective against nits.
Adult
150-200 mcg/kg/d PO as single dose; alternatively, 12 mg PO as single dose; may repeat in 1 wk prn
Pediatric
<5 years: Not established and not recommended
>5 years: 0.2 mg/kg PO as single dose; alternatively, administer as in adults
May interact with other ligand-gated chloride channels, such as those gated by GABA
Documented hypersensitivity
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Treat mothers who intend to breastfeed only when risk of delayed treatment outweighs possible risks to the newborn caused by ivermectin excretion in milk
Repeat courses of therapy may be required in immunocompromised patients
May cause nausea, vomiting, and mild CNS depression; may cause drowsiness
More on Pediculosis |
| Overview: Pediculosis |
| Differential Diagnoses & Workup: Pediculosis |
 Treatment & Medication: Pediculosis |
| Follow-up: Pediculosis |
| Multimedia: Pediculosis |
| References |
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References
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Further Reading
Keywords
pediculosis, lice, lice infestation, Pediculus humanus capitis, head louse, head lice, Pediculus humanus corporis, body louse, body lice, Pthirus pubis, pubic louse, pubic lice, lice eggs, nits, typhus, trench fever, relapsing fever, cervical lymphadenopathy, conjunctivitis, human immunodeficiency virus, HIV, syphilis, gonorrhea, chlamydia, genital herpes, trichomonas
