Permethrin is a synthetic pyrethroid (insecticide) indicated for the treatment of lice (pediculosis), knits (lice eggs) and scabies, and works by paralyzing or killing these parasites to relieve symptoms like rash and intensely itchy skin.

Possible side effects of permethrin treatment include itchiness and redness of the skin and a burning or numbing sensation. For this reason it is important to only use permethrin as directed by your primary care provider, dermatologist, or pediatrician.

Permethrin can be purchased at pharmacies and drug stores in the form of a lotion or a cream, and is sold under the brand names Nix, Elimite, and Acticin.

Indications for use

Permethrin is indicated for treatment of the following types of infestations:

Lice (pediculosis);
Nits (lice eggs);
Scabies.

There are different strengths of permethrin, which comes in the form of a lotion and a cream. Make sure to ask your healthcare provider about which formulation to choose.

Confirming a diagnosis

Your primary care provider or dermatologist will be able to evaluate your symptoms, diagnosis the type of infestation (lice or scabies), and prescribe the most appropriate treatment.

How to use

Permethrin should only be used on the skin and scalp, and should not be ingested. The following formulations are prescribed depending on the indication for treatment:

1. Permethrin 1% lotion

Permethrin 1% lotion is indicated for the treatment of pediculosis (lice and nits) and can be used in the following way:

Adults and children over 2 years of age: shake the bottle well before use. Apply to damp hair, making sure to cover the whole scalp. Massage the lotion into the scalp and make sure to scrub the neck and behind the ears. Leave in place for 10 minutes, then run a fine-toothed comb through your hair to remove any lice. Finally, rinse well and dry your hair with a clean towel.

Depending on the amount of hair, it may be necessary to use more than one bottle. If lice are still present, it may be necessary to reapply the treatment after 7 days.

2. Permethrin 5% cream

Permethrin 5% cream is indicated for the treatment of scabies and should be applied according to the instructions below:

Adults and children over 2 months of age: massage the product into the skin from head to toe. For babies, apply also to the scalp and neck. Leave the product on for 8 to 14 hours and then rinse off with water.

Itchy skin is common after this treatment, however make sure to contact your doctor or healthcare provider if it lasts for more than 14 days.

Babies under 2 months of age should be treated with permethrin 5% lotion as directed by a pediatrician.

Side effects

Possible side effects of permethrin include:

Numbness, tingling, or burning sensation of the skin;
Localized pain or discomfort in the area where the treatment is applied;
Redness, itchiness, and irritation of the skin.

These effects are typically mild and improve within a few days following treatment.

Stop using the medication and call your provider right away if you experience symptoms like intense redness or itchiness of the skin, as these could be signs of an allergic reaction.

Does permethrin make your skin itch?

The itchiness caused by permethrin is typically mild and tends to resolve itself within 4 weeks without the need for any specific treatment.

Applying moisturizing creams to the skin and taking cold baths can help calm itchy skin.

Check out home remedies for itchy skin.

Contraindications to use

Permethrin is contraindicated in people with a history of an allergy to medications containing synthetic pyrethroids or pyrethrin in their formulas. It should not be applied to areas of inflammation, broken skin, or burns.

People who are pregnant or breastfeeding should talk to their healthcare provider before using permethrin. Dosing for children under 2 years of age for the 1% lotion, and under 2 months of age for the 5% cream, needs to be determined by a pediatrician.