Lice - Diagnosis and treatment (2024)

Diagnosis

During an exam, a health care provider may use a magnifying lens to look for lice. The provider may also use a special light, called a Wood's light, to check for nits. This light makes the nits easier to spot by making them look pale blue.

Head lice

A health care provider may diagnose head lice after finding a live young or adult louse in the person's hair or on the scalp, or after seeing one or more nits on hair shafts found within 1/4 inch (6 millimeters) of the scalp.

Body lice

A health care provider may diagnose body lice if they find eggs or crawling lice in clothing seams or on bedding. You can see a body louse on skin if it crawls there to feed.

Pubic lice

A health care provider may diagnose pubic lice when they see moving lice or nits on hair in the pubic area or on other areas of coarse hair, such as chest hair, eyebrows or eyelashes.

Treatment

Use drugs that treat lice only as directed. Applying too much can cause red, irritated skin.

Head lice

Head lice treatment may involve:

  • Nonprescription products. Shampoos containing permethrin (Nix) are usually the first option used to combat lice. Permethrin is a synthetic version of pyrethrin, which is a chemical compound extracted from the chrysanthemum flower. Permethrin is toxic to lice. Follow the directions closely when using this product.

    A lotion containing ivermectin (Sklice) also is available without a prescription. Ivermectin is toxic to lice. The lotion is approved for use in adults and children age 6 months or older. You can apply it once to dry hair and then rinse with water after 10 minutes.

    Don't repeat the ivermectin treatment without talking to your health care provider first. Possible side effects include eye irritation or redness, dandruff, dry skin, and a burning sensation at the application site.

    In some locations, lice have grown resistant to the ingredients in nonprescription treatments. If nonprescription treatments don't work, your health care provider can prescribe shampoos or lotions that contain different ingredients.

  • Oral prescription drug. Ivermectin (Stromectol) is available by prescription as a tablet taken by mouth. The oral drug effectively treats lice with two doses, eight days apart. This drug is typically used when other treatments haven't been effective.

    Children must weigh at least 33 pounds (15 kilograms) to take oral ivermectin. Side effects may include nausea and vomiting.

  • Topical prescription drugs. Malathion is a prescription drug that you apply to the hair and then rub into the hair and scalp. Malathion has a high alcohol content and is flammable. So keep it away from heat sources such as hair dryers, electric curlers and cigarettes.

    If you're pregnant or breastfeeding, talk to your health care provider before using this drug. The drug isn't recommended for children 2 and under. It's not clear if it's safe for use in 2- to 6-year-olds.

    Spinosad (Natroba) is a newer prescription treatment for head lice. You can apply it to dry hair and the scalp for 10 minutes and then rinse with water. The treatment doesn't usually need to be repeated. But it can be used again after seven days if live lice are still present.

    Possible side effects of spinosad include redness or irritation of the eyes and skin. This drug isn't recommended for children younger than age 4.

Body lice

If you have body lice, first bathe with soap and water. After bathing, apply permethrin (Nix) to the affected areas before bedtime and then shower in the morning. Repeat this treatment nine days after the first application.

Also take other measures to get rid of body lice. Wash clothing and bedding with hot, soapy water — at least 130 F (54 C) — and dry them at high heat for at least 20 minutes. Vacuum the floors and furniture. And seal unwashable items in an airtight bag for two weeks.

Pubic lice

Pubic lice can be treated with many of the same nonprescription and prescription treatments used for head lice. Carefully follow the package instructions. Talk to your health care provider about treatment of lice and nits on eyebrows or eyelashes.

Self-care

Whether you use nonprescription or prescription shampoo to kill lice, much of the treatment involves self-care steps you can take at home. These include making sure all the nits are removed and that all clothing, bedding, personal items and furniture are free of lice.

In most cases, killing lice that are on you isn't difficult. The challenge is getting rid of all the nits and avoiding contact with other lice at home or school.

Request an appointment

Lifestyle and home remedies

You can get rid of lice with a patient, detailed approach that involves cleaning yourself or your child and any personal belongings that may contain lice.

These steps may help you get rid of lice:

  • Check other household members for lice and nits. Treat anyone who has signs of lice.
  • Use lotions and shampoos. Choose from among several nonprescription lotions and shampoos designed to kill lice. Apply the product according to package instructions.

    You may need to repeat treatment with the lotion or shampoo in about 9 to 10 days after the first application. Be sure to check the age recommendations of the drugs before using them on children.

  • Comb wet hair. Use a fine-toothed or nit comb to physically remove the lice from wet hair. Repeat every 3 to 4 days for at least two weeks. This method may be used in combination with other treatments. It is usually recommended as the first line treatment for infants younger than 2 months.
  • Wash items. Wash bedding, stuffed animals, clothing and hats with hot, soapy water — at least 130 F (54 C) — and dry them at high heat for at least 20 minutes.
  • Seal unwashable items. Place them in an airtight bag for two weeks.
  • Vacuum. Vacuum the floor and furniture well.
  • Wash combs and brushes. Use very hot, soapy water — at least 130 F (54 C) — or soak combs and brushes in rubbing alcohol for an hour.

One thing you don't need to worry about is your household pets. Lice prefer people to pets. So your pets don't need any treatment for lice.

Alternative medicine

Many home or natural remedies, such as mayonnaise or olive oil, are used to treat head lice. But there's little to no evidence of their effectiveness.

A special machine that uses hot air to dehydrate head lice and their eggs is another alternative treatment method. The machine requires special training and is currently available only at professional lice treatment centers.

A regular hair dryer can't be used to do this at home because it's too hot and could burn the scalp. The machine that dehydrates lice is cooler than most hair dryers but has a much higher flow rate to kill the lice by drying them out.

Preparing for your appointment

Often, you can get rid of lice with nonprescription treatments and by properly washing household items that had lice on them, such as sheets, towels and clothes. If these steps don't work, see your health care provider.

Here's some information to help you get ready for your appointment and what to expect from your provider.

What you can do

  • Write down any symptoms you're experiencing, including any that may seem unrelated to the reason for which you scheduled the appointment.
  • Write down key personal information, including when you might have been exposed to lice, whom you might have exposed and what household items might be contaminated.
  • Make a list of all medications, vitamins or supplements that you're taking.
  • Write down questions to ask your health care provider. Your time with your provider is limited, so preparing a list of questions ahead of time will help you make the most of your time together. List your questions from most important to least important in case time runs out.

Some basic questions to ask your health care provider about lice include:

  • How do I treat lice?
  • Is there a generic alternative to the medicine you're prescribing?
  • How often can I safely use this product?
  • How do I get rid of lice from household items?
  • Who do I need to inform about my condition?
  • What other actions do I need to take to avoid getting lice again or giving it to others?
  • Are there any brochures or other printed material that I can take home with me? What websites do you recommend?
  • Should I plan for a follow-up visit?

In addition to the questions that you've prepared to ask your health care provider, don't hesitate to ask questions during your appointment when you don't understand something.

What to expect from your doctor

Your health care provider is likely to ask you a number of questions, such as:

  • When did you first begin experiencing symptoms?
  • How were you exposed to lice?
  • Is there anyone you might have exposed to lice?
  • How severe are your symptoms?

What you can do in the meantime

If you think or know you have lice, avoid sharing personal items, bedding, towels or clothing. Bathe and follow self-care measures, including washing items in hot water.

If you think or know you have pubic lice, also avoid sexual activity until you've been treated.

By Mayo Clinic Staff

Lice - Diagnosis and treatment (2024)

FAQs

What is the diagnosis for lice? ›

A health care provider may diagnose head lice after finding a live young or adult louse in the person's hair or on the scalp, or after seeing one or more nits on hair shafts found within 1/4 inch (6 millimeters) of the scalp.

How long do you need to isolate if you have lice? ›

Treat head lice as soon as you spot them. You do not need to see your GP. Check everyone in the home and treat them on the same day if they have head lice. There's no need for children to stay off school if they have head lice.

Can head lice live on pillows and sheets? ›

Head lice do not live on pillows or sheets, as they need to feed on the scalp of a host in order to survive. According to the CDC, lice can only survive for 48 hours after falling from a host scalp.

How long should you stay out of work if you have lice? ›

Unless your employer has a 'no-nit' policy, then there is no reason you cannot go to work if you have head lice. There is no guidance saying children should be kept off school if they have head lice,3 so the likelihood of your employer wanting you to stay off work will be low.

How do you self diagnose head lice? ›

Look for lice crawling on the scalp where the hair is parted or on the hair shaft. The lice will be dark in color and the size of a poppyseed. Look for nits near hair follicle about ¼ inch from scalp. Nits (eggs) will be white or yellowish-brown.

How do you diagnose public lice? ›

Pubic lice are short and crab-like and appear very different from head and body lice. Pubic lice infestation is diagnosed by finding a “crab” louse or eggs on hair in the pubic region or, less commonly, elsewhere on the body (eyebrows, eyelashes, beard, mustache, armpit, perianal area, groin, trunk, scalp).

Do I need to wash bedding everyday with lice? ›

Research suggests that bed linen, hats, clothing and furniture do not harbour or transmit lice or nits and that there is no benefit in washing them as a treatment option. Nits and lice only live on the human head. They quickly dehydrate and die if removed from the head.

Do I need to clean my house after head lice? ›

Go to a lice clinic to safely and efficiently treat the lice. After a lice infestation, it is good to thoroughly clean your home. Once you've ensured you or your family is free of head lice, you'll want to address any items in the house that may still harbor lice and eggs.

What kills lice immediately? ›

Washing, soaking, or drying items at a temperature greater than 130°F can kill both head lice and nits. Dry cleaning also kills head lice and nits.

Can lice survive a washing machine? ›

You can kill lice on clothing, pillows, blankets, and other washable items in one day by running them through a hot cycle in both the washer and dryer. The infestation must still be removed from each infected person and other areas of your home with soaps and sprays specifically intended for the treatment of lice.

Will lice go away on their own? ›

Lice are parasites that feed on human blood and can be found on people's bodies. There are treatments for the itching caused by lice bites but they do not get rid of the infestation. Lice will not go away on their own. The infestation needs to be treated.

What do I need to clean if my child has lice? ›

It's important to wash any machine washable items. Clothing, bedding, towels, stuffed animals, etc., that came in contact with the lice up to two days before treatment needs to be washed. It's important not to let anyone else come in contact with these items until they have been properly cleaned.

Should I freak out if I have lice? ›

1) Lice don't carry disease.

They'll make one's scalp feel itchy, and scratching can lead to some scabs. Too much scratching anywhere can lead to secondary infections (bacteria on the outside getting “under” the skin and growing there). But the lice themselves don't cause serious health problems.

Do dead lice fall out of hair? ›

The female louse secretes this glue-like substance when she lays her eggs to protect them until they hatch. The glue hardens upon secretion and does not dissipate when a nit dies. For that reason, dead lice remain cemented onto the hair shaft until you manually or chemically remove them or the hair grows out.

What if I still feel crawling after lice treatment? ›

If some are still present but moving slowly, do not shampoo again. If lice are still active and no dead lice are found, call your health care provider. These lice may be resistant to the medicine. Do not use more than one head lice medicine at a time without asking your doctor.

What is the diagnosis code for lice? ›

Pediculosis due to Pediculus humanus capitis

B85. 0 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes. The 2024 edition of ICD-10-CM B85. 0 became effective on October 1, 2023.

What is the medical term for lice? ›

In humans, louse infestation is known as pediculosis if caused by head or body lice, and as pthiriasis if caused by pubic lice. Pediculosis is a contagious parasitic infestation, transmitted from human-to-human by close contact or, in body lice, via infested clothes or bed linen.

What disease is associated with lice? ›

Body lice are known to transmit bacterial infections that cause three human diseases: louse-borne typhus (Rickettsia prowazeki), trench fever (Rochalimaea quintana), and louse-borne relapsing fever (Borrelia recurrentis).

How do you diagnose lice in animals? ›

Usually, the diagnosis is made by seeing lice or eggs on the infested pet. Parting the hair often reveals the lice. Chewing lice are active and can be seen moving through the hair. Sucking lice usually move more slowly.

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