Treatment algorithm

Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups: see disclaimer

ACUTE

children aged <2 months

1st line – mechanical removal

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ACUTE
|
children aged <2 months
1st line – 

mechanical removal

Head lice rarely occur in this age group. Mechanical removal can be safely used. If a patient in this age group has head lice, the infestation is likely to be minimal and individual head lice can easily be seen as the hair is very thin. It is better to remove these few head lice by hand instead of putting newborns at risk of adverse effects from other treatments.

Plus – treatment of contacts

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ACUTE
|
children aged <2 months
Plus – 

treatment of contacts

Treatment recommended for ALL patients in selected patient group

Household and other close contacts of infested individuals should be examined and treated if infested. Some experts recommend prophylactic treatment of household contacts, particularly siblings of the infested individual.[2][3][4]

children aged ≥2 months and <2 years

1st line – pediculicide

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ACUTE
|
children aged ≥2 months and <2 years
1st line – 

pediculicide

Dimeticones are the first-line agent in these patients. They have the advantage of being nontoxic and are highly effective. Due to their physical mode of action, development of resistance is highly unlikely. Permethrin 1%, or pyrethrins plus piperonyl butoxide, may also be considered. Human toxicity seems to be low in adults.[84]​ Pyrethrins have slightly higher absorption rates compared with permethrin 1%; they can cause allergic reactions in individuals sensitive to ragweed, and should be avoided in patients allergic to chrysanthemums. Because neither product is ovicidal, experts suggest treatment at days 0 and 8-10.[45][85]​ There is widespread resistance to permethrin 1% or pyrethrins plus piperonyl butoxide products, especially where they have been widely used over many years. Resistance patterns are complex and are usually not known for the location in which the patient lives.[48][49][50][51][52]​ There are also safety concerns.[53][54]

Local guidance should be consulted when selecting a specific pediculicide.[47]

Manufacturer's directions for use need to be followed closely to ensure a safe and effective outcome. Parents need to be informed and reassured that seeing live lice (nymphs) after the first treatment does not indicate treatment failure or resistance, and they should continue to administer the additional treatments at the recommended intervals.

Ivermectin topical lotion, or spinosad are recommended in the US in areas with known resistance to first-line drugs.[10] Benzyl alcohol is also used in some countries, but is not available in the US. Recommendations for alternative options in other countries may differ and depend on availability. Local guidelines should be consulted.

Primary options

dimeticone topical: apply to the hair and scalp as directed, leave for 30 minutes to 8 hours (depending on product) before rinsing; repeat treatment after 8-10 days

OR

permethrin topical: (1%) apply to the hair and scalp as directed, leave for 10 minutes before rinsing

OR

pyrethrin topical: apply to the hair and scalp as directed, leave for 10 minutes before rinsing

Secondary options

benzyl alcohol lotion: infants ≥6 months of age: (5%) apply to the hair and scalp as directed, leave for 10 minutes before rinsing

OR

ivermectin topical: infants ≥6 months of age: (0.5%) apply to the hair and scalp as directed, leave for 10 minutes before rinsing

OR

spinosad topical: infants ≥6 months of age: (0.9%) apply to the hair and scalp as directed, leave for 10 minutes before rinsing

Plus – treatment of contacts

Back
ACUTE
|
children aged ≥2 months and <2 years
Plus – 

treatment of contacts

Treatment recommended for ALL patients in selected patient group

Household and other close contacts of infested individuals should be examined and treated if infested. Some experts recommend prophylactic treatment of household contacts, particularly siblings of the infested individual.[2][3][4]

2nd line – mechanical removal or occlusive agent

Back
ACUTE
|
children aged ≥2 months and <2 years
2nd line – 

mechanical removal or occlusive agent

Patients who cannot or do not want to use pediculicides with a neurotoxic mode of action, or run the risk of inducing resistance, can use mechanical removal.

Mechanical removal methods include nit picking, shaving hair, or the preferred method, wet combing. Occlusive agents that may be used in this age group include petroleum jelly.

Nit picking (removal of eggs and hatched egg casing) is generally not recommended as the sole technique for eradication of an infestation. If undertaken, a fine-toothed, metal lice comb can aid in removal of the nits.[13][59]

Wet combing involves shampooing or conditioning hair twice a week with ordinary shampoo, then vigorous combing out of wet hair with a special fine-toothed comb. Success can be variable and depends largely on good technique.[61][62][63]

Petroleum jelly is thought to obstruct the respiratory spiracles of the adult louse and block holes in the operculum of the eggs. About 30-40 g of standard petroleum jelly is massaged on the entire surface of the hair and scalp and left on overnight. Repeated shampooing over the following 7-10 days removes the residue, and nits should be removed.

Re-infestation can be treated as for initial infestation.

Plus – treatment of contacts

Back
ACUTE
|
children aged ≥2 months and <2 years
Plus – 

treatment of contacts

Treatment recommended for ALL patients in selected patient group

Household and other close contacts of infested individuals should be examined and treated if infested. Some experts recommend prophylactic treatment of household contacts, particularly siblings of the infested individual.[2][3][4]

children aged ≥2 years and adults

1st line – pediculicide

Back
ACUTE
|
children aged ≥2 years and adults
1st line – 

pediculicide

Dimeticones are the first-line agent in these patients. They have the advantage of being nontoxic and are highly effective. Due to their physical mode of action, development of resistance is highly unlikely. Permethrin 1%, or pyrethrins plus piperonyl butoxide, may also be considered. Human toxicity seems to be low in adults.[84] ​Pyrethrins have slightly higher absorption rates compared with permethrin 1%; they can cause allergic reactions in individuals sensitive to ragweed, and should be avoided in patients allergic to chrysanthemums. Because neither product is ovicidal, experts suggest treatment at days 0 and 8-10.[45][85]​​ There is widespread resistance to permethrin 1% or pyrethrins plus piperonyl butoxide products, especially where they have been widely used over many years. Resistance patterns are complex and are usually not known for the location in which the patient lives.[48][49][50][51][52]​​ There are also safety concerns.[53][54]

Isopropyl myristate/cyclomethicone is an alternative option in some regions and should not be used in children under 4 years old.[10][55]

Local guidance should be consulted when selecting a specific pediculicide.[47]

Manufacturer's directions for use need to be followed closely to ensure a safe and effective outcome. Parents need to be informed and reassured that seeing live lice (nymphs) after the first treatment does not indicate treatment failure or resistance, and they should continue to administer the additional treatments at the recommended intervals.

Ivermectin topical lotion, or spinosad are recommended in the US in areas with known resistance to first-line drugs.[10] Benzyl alcohol is also used in some countries, but is not available in the US. Recommendations for alternative options in other countries may differ and depend on availability. Local guidelines should be consulted.

Malathion is an organophosphate (cholinesterase inhibitor). Due to reports of cross-resistance with pyrethroids and safety concerns (it is highly flammable), it is considered a third-line treatment.[86][87][88][89] Although head lice resistant to malathion are common in the UK, where it has been used for decades, the preparation available in the US contains additional ingredients that themselves have a 50% cure rate, and this may delay development of resistance in the US.

Most pediculicides can be used in pregnant women. However, all agents should be used with caution in lactation due to a lack of data. For women who want an extra margin of safety, mechanical removal or compounds with a physical mode of action can be safely used instead.

Primary options

dimeticone topical: apply to the hair and scalp as directed, leave for 30 minutes to 8 hours (depending on product) before rinsing; repeat treatment after 8-10 days

OR

permethrin topical: (1%) apply to the hair and scalp as directed, leave for 10 minutes before rinsing

OR

pyrethrin topical: apply to the hair and scalp as directed, leave for 10 minutes before rinsing

OR

isopropyl myristate/cyclomethicone topical: children ≥4 years of age and adults: apply to the hair and scalp as directed, leave for 10 minutes before rinsing

Secondary options

benzyl alcohol lotion: (5%) apply to the hair and scalp as directed, leave for 10 minutes before rinsing

OR

ivermectin topical: (0.5%) apply to the hair and scalp as directed, leave for 10 minutes before rinsing

OR

spinosad topical: (0.9%) apply to the hair and scalp as directed, leave for 10 minutes before rinsing

Tertiary options

malathion topical: (0.5%) apply to the hair and scalp as directed, leave for 8-12 hours before rinsing

Plus – treatment of contacts

Back
ACUTE
|
children aged ≥2 years and adults
Plus – 

treatment of contacts

Treatment recommended for ALL patients in selected patient group

Household and other close contacts of infested individuals should be examined and treated if infested. Some experts recommend prophylactic treatment of household contacts, particularly siblings of the infested individual. Children should not be excluded or sent home early from school because of head lice. Parents of infested children (defined by visualisation of live lice) should be notified and informed that their child should be treated, ideally, before returning to school the next day. The presence of nits alone does not justify treatment.[2][3][4]

2nd line – mechanical removal or occlusive agent

Back
ACUTE
|
children aged ≥2 years and adults
2nd line – 

mechanical removal or occlusive agent

Patients who cannot or do not want to use pediculicides with a neurotoxic mode of action, or run the risk of inducing resistance, may use mechanical removal.

Mechanical removal methods include nit picking, shaving hair, or the preferred method, wet combing.

Nit picking (removal of eggs and hatched egg casing) is generally not recommended as the sole technique for eradication of an infestation. If undertaken, a fine-toothed, metal lice comb can aid in removal of the nits.[13][59]

Wet combing involves shampooing or conditioning hair twice a week with ordinary shampoo, then vigorous combing out of wet hair with a special fine-toothed comb. Success can be variable and depends largely on good technique.[61][62][63]

Occlusive agents that may be used in this age group include petroleum jelly, or use of the Nuvo method.

Petroleum jelly is thought to obstruct the respiratory spiracles of the adult louse and block holes in the operculum of the eggs. About 30-40 g of standard petroleum jelly is massaged on the entire surface of the hair and scalp and left on overnight. Repeated shampooing over the following 7-10 days removes the residue, and nits should be removed.

The Nuvo method uses Cetaphil® cleanser (a hydrating emollient containing glycerin) applied to the hair and scalp, dried on with a blow-drier, then washed out 8 hours later, with the treatment repeated once a week for 3 weeks.[82][83]

Re-infestation can be treated as for initial infestation.

Plus – treatment of contacts

Back
ACUTE
|
children aged ≥2 years and adults
Plus – 

treatment of contacts

Treatment recommended for ALL patients in selected patient group

Household and other close contacts of infested individuals should be examined and treated if infested. Some experts recommend prophylactic treatment of household contacts, particularly siblings of the infested individual. Children should not be excluded or sent home early from school because of head lice. Parents of infested children (defined by visualisation of live lice) should be notified and informed that their child should be treated, ideally, before returning to school the next day. The presence of nits alone does not justify treatment.[2][3][4]

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Choose a patient group to see our recommendations

Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups. See disclaimer

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