Signs and Symptoms of Lice

Lice infestations are something that every parent dreads. But it's not just head lice that people should be worried about; there are other types of lice that can affect other parts of the body and be easy to get.

Sometimes it takes a while before you even notice lice symptoms, with niggling, little itches often going unrecognized until the infestation is severe. It is important, therefore, to know the signs and symptoms of a lice infestation—including what lice look like—so that you can get treated before you pass them on to other people.

lice symptoms

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Frequent Symptoms

Lice are wingless insects of the Phthiraptera order, of which there are over 5,000 species. Some species are chewing lice that feed off the skin and debris on their hosts. Those affecting humans tend to be blood-sucking species that rely on blood and other secretions to survive.

Broadly speaking, there are three types of lice infestations (pediculosis) that occur in humans:

  • Head lice (Pediculus humanus capitis)
  • Body lice (Pediculus humanus corporis)
  • Pubic lice (Pthirus pubis)

While the symptoms of hair, body, and pubic lice are similar, their location and the way in which they spread differ.

Head Lice

Head lice are most common among children ages 3 to 11 and are readily transmitted by close contact in daycare and schools. Within that age group alone, up to 12 million infestations occur in the United States each year. When school outbreaks occur, the infestation can easily be spread to family members and others.

Despite what some people think, head lice infestations are not a sign of poor hygiene.

Head lice reside close to the scalp but can also be found in the eyelashes and eyebrows. The insects don't jump or fly but rather crawl around on the skin using their claw-like legs. They tend to be most active at night and they can interfere with sleep.

The signs and symptoms of a head lice infestation include:

  • A tickling sensation on the scalp as if something is crawling
  • Scalp itchiness, causing frequent head scratching
  • Difficulty sleeping accompanied by daytime irritability
  • Sores on the scalp from prolonged scratching

Body Lice

Unlike head lice, body lice are associated with poor hygiene. Infestations are common among the homeless and people living in shelters. People who do not have the opportunity to bathe or change clothes at least once weekly are at greatest risk.

Another difference between head lice and body lice is that body lice are generally found in the clothes and bedding of affected people. While there may be eggs attached to body hair, the nits are mainly concentrated in the seams of clothes and bedding. Body lice may be seen on the skin when they are there to feed.

Signs and symptoms of a body lice infestation include:

  • Intense itchiness and scratching, particularly around the waistline, groin, and upper thighs
  • Darkening and thickening of the skin due to long-term scratching
  • The development of open sores due to secondary bacterial or fungal infections

Pubic Lice ("Crabs")

While head lice and body lice are variations of the same species, pubic lice (also known as "crabs") are a different species with a different physical structure and mode of transmission. Public lice mainly reside in pubic hair but can also be found on other parts of the body where there is coarse hair, such as the legs, armpits, mustache, beard, eyebrows, or eyelashes.

Crabs are primarily spread by sexual contact and occasionally by infested clothing or bedding. Crabs on the eyebrows or eyelashes of children may be signs of sexual abuse.

Signs and symptoms of pubic lice infestation include:

  • Itching and scratching in the genital region
  • Darkening of the skin due to prolonged scratching of an untreated infestation

Because pubic lice are mainly transmitted by sexual contact, your healthcare provider may advise you to undergo screening for sexually transmitted diseases that can sometimes co-occur with crabs.

Visual Signs

Once you recognize the physical signs of an infestation (such as relentless scratching), you can usually examine the affected area and confirm your suspicions. This can sometimes be done with the naked eye; in other cases, a magnifying glass may be needed.

When inspecting for lice, it is important to understand that all lice—whether on the head, body, or genitals—have three distinct forms:

  • Nits (lice eggs)
  • Nymphs (immature lice that hatch from nits)
  • Adults (fully grown lice that are able to reproduce)

Depending on the type of lice a person has, the appearance and location of the nits, nymphs, and adult lice can differ.

Head Lice

Adult head lice can often be seen with the naked eye. Fully grown adults are roughly the size and shape of a sesame seed with six legs and a tannish to grayish-white color. The front two legs have larger claws that help them crawl around.

Nymphs are smaller than adults and more difficult to see. They are generally lighter in color but are otherwise similar in appearance to adults.

You may also be able to see nits, which look like dandruff-like flecks or tiny droplets on the hair shaft itself. Upon closer inspection, the eggs will be oval-shaped, whitish to light yellow in color, and located near the base of the hair shaft. If your hair is light-colored, the eggs can be difficult to see.

Body Lice

Body lice are similar to head lice because they belong to the same species. Adults are also the size and shape of a sesame seed with six legs and the same beige to grayish-white coloration. Nymphs and nits are also similar in appearance.

The main difference is their location on the body. Unlike head lice, body lice mainly reside in clothing or bedding and only move to the body when they are ready to feed. Although nits may be found on hair shafts, they mainly are located in the seams of clothing or bedding.

Therefore, a physical inspection of body lice should not only involve the body of the affected individual but their clothes and bedding as well.

Public Lice ("Crabs")

Pubic lice ("crabs") can be difficult to see with the naked eye and may require a magnifying glass to visualize the infestation.

As their nickname suggests, adult crabs look like tiny crabs with roundish bodies and six legs. The front two legs have claw-like pinchers. The color of pubic lice can also range from grayish-white to beige. Females are usually larger than males.

Nymphs are smaller than adults and can be difficult to spot with the naked eye, particularly on different skin tones or hair colors.

As with head lice, pubic lice lay their eggs on the base of hair shafts. The oval-shaped eggs are a whitish to yellowish color and are sometimes difficult to remove without a fine-tooth lice comb.

Complications

Along with discomfort, emotional distress, and sleep disturbance, head lice can lead to a number of complications when left untreated. For example, frequent scratching can cause breaks in the skin that can leave you vulnerable to infection.

Since lice feed on human blood, severe, chronic infestations can lead to blood loss and iron deficiency anemia. In addition, an allergic reaction to louse feces or bites may trigger a rash in some individuals.

Know that in most cases these complications are rare. Lice are generally harmless, but they are important to get rid of.

When to See a Healthcare Provider

If you suspect that you or your child has lice, a physical inspection of the affected area can usually—but not always—confirm your suspicions. If the exposure was recent (or you just learned of an outbreak at school or were informed that a sex partner has crabs), you may not see any clear evidence of an infestation. The lack of physical evidence doesn't mean that you are in the clear.

Lice can be mistaken for many things, particularly in the early stages. What you may assume to be dandruff, acne, or insect bites may later evolve into a full-blown lice infestation. By this stage, others may be affected.

If you suspect that you or your child has lice, call your healthcare provider. While there are numerous over-the-counter lotions, mousses, and shampoos available to treat lice infestations, some products may be less effective for certain types of infestations.

There is evidence that certain subspecies of lice may be developing resistance to drugs commonly used to treat infestations, including pyrethrin found in products like Rid and Triple-X.

Moreover, the treatments that work for head or body lice may not work for pubic lice or vice versa.

A Word From Verywell

As distressing as it can be to hear that you or your child has lice, infestations are readily treatable. If using an over-the-counter lice killer (pediculicide), follow the instructions carefully and use a lice comb to remove any eggs attached to hair follicles.

Clothing, bedding, and towels used by an affected person should be laundered in hot water (at least 130 degrees F) and machine dried using the hot cycle. Clothing and items that are not washable can be drycleaned or sealed in a plastic bag for two weeks.

If you have lice and are too embarrassed to speak with your healthcare provider or pharmacist, consider using a telehealth practitioner who can ensure you get the correct treatment and may even be able to prescribe medications for you.

Frequently Asked Questions

  • How long after exposure do lice symptoms appear?

    Adult lice will start laying eggs the moment they infest a host. Symptoms can begin when the nits start hatching into nymphs. For head lice, this can take around eight to nine days. Body lice take slightly longer, around one to two weeks, while pubic lice nits hatch in between six and 10 days. The intensity of symptoms will increase as the lice population grows.

  • What are the symptoms of lice?

    Itching is the main symptom of all lice infestations. For head lice, the main affected area will be the scalp, while body lice can cause intense itchiness around the groin, waistline, and upper thighs. As per their name, pubic lice ("crabs") mainly affect pubic hair, causing itchiness in the genital area. Prolonged scratching can lead to sores and infection, particularly with head or body lice.

Head Lice Doctor Discussion Guide

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8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  4. Centers for Disease Control and Prevention. Pubic "crab" lice: frequently asked questions. Updated September 17, 2020.

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  6. Althomali SA, Alzubaidi LM, Alkhaldi DM. Severe iron deficiency anaemia associated with heavy lice infestation in a young woman. BMJ Case Rep. 2015;2015:bcr2015212207. doi:10.1136/bcr-2015-212207

  7. Centers for Disease Control and Prevention. Head lice: treatment. Updated October 15, 2019.

  8. Centers for Disease Control and Prevention. Pubic "crab" lice: treatment. Updated September 12, 2019.