Fleas and lice are different parasitic insects that can cause an itchy reaction on the skin. Though similar, they possess unique traits. For example, fleas can jump, but lice can only crawl.

Fleas are wingless parasitic insects that consume the blood of a host animal, including humans. They move from one host to another through jumping.

Head lice are another form of parasitic insect that feed on human blood. They also do not have wings and cannot fly. Instead, they move from host to host through crawling. Some people refer to them simply as “lice.”

This article reviews the similarities and differences between lice and fleas, including their symptoms, causes, treatment, and prevention. It also gives answers to some common questions about the parasitic insects.

A photo collage of a flea and a head louse 1Share on Pinterest
Design by MNT; Photography by Ed Reschke/Getty Images

The following sections provide information on the symptoms associated with fleas and head lice.

Fleas

Fleas typically cause itching in the area where they bite into a person’s skin. They may also cause inflammation and the appearance of a rash.

In rare cases, they can transmit conditions such as:

  • bubonic plague
  • typhus
  • protozoan infestations
  • rickettsial disease (commonly from ectoparasites)
  • helminth infestations

If a person develops a disease from a flea bite, they may also experience symptoms associated with the underlying medical condition.

Head lice

According to the Centers for Disease Control and Prevention (CDC), head lice do not transmit disease.

In some cases, head lice may not cause any symptoms. Asymptomatic infestations often occur in light or first-time infestations.

It can take 4–6 weeks before a person develops a reaction to lice bites and develops symptoms. When symptoms do develop, they may include:

The following sections provide information on the causes of fleas and head lice.

Fleas

In the United States and other higher income countries, dogs and cats are common sources for humans to come into contact with a flea. Other household pets may also come in contact with fleas, which then transmit to people caring for the pets.

Risk factors for coming in contact with fleas include:

  • living with pets that go outdoors
  • being in close proximity to wild animals
  • difficulty cleaning the home regularly, particularly if someone has pets

Head lice

Unlike fleas, lice cannot jump. They also cannot fly. Head lice transmit between people through close personal contact.

Lice can transmit through:

  • direct head-to-head contact
  • sharing personal items, such as hats or other objects placed on the head
  • contact with other objects, such as pillows or bedsheets, which may harbor lice

Each year, around 6–12 million cases of head lice occur in the U.S. in children ages 3–11 years old. The condition is much less common among people of African American heritage than people of other races. However, head lice can affect anyone.

The following sections describe treatments for fleas and head lice.

Fleas

Treatment for fleas often addresses symptoms. A person also needs to take steps to remove the fleas from the home and other living environments. This may include treating pets following a veterinarian’s instructions and thoroughly cleaning the home.

Treatment for symptoms may include one or more of the following:

  • Topical medications: For example, lotions or creams may help with the swelling and itchiness of flea bites. Creams may contain ingredients such as:
  • Oral medications: A doctor may recommend a person takes oral antihistamines, such as loratadine or cetirizine, to help ease itchiness. For severe swelling, a doctor may prescribe corticosteroids.
  • Home remedies: A person may find relief from itching and inflammation with home remedies, such as by applying a cold compress to the affected area.

Learn more about how to get rid of fleas.

Head lice

Head lice treatment often involves applying topical medications to a person’s hair and scalp, such as lice shampoo. These medications may paralyze or suffocate lice.

Current treatments do not reliably destroy lice eggs, so a person will typically require more than one treatment application, with about a week between applications.

Common medications for head lice include:

  • permethrin
  • spinosad
  • malathion
  • pyrethrins combined with piperonyl butoxide
  • benzyl alcohol
  • ivermectin

The following sections provide tips on helping to prevent contracting fleas and head lice.

Fleas

Fleas prefer humid, warm areas. They lay their eggs on a host, such as a cat or dog.

According to the CDC, ways to help prevent fleas at home include:

Head lice

A person can take similar steps to help prevent head lice. Some prevention methods include:

  • regularly cleaning the house, including vacuuming rugs
  • discouraging children from engaging in direct head-to-head contact
  • not sharing personal items, such as hats or brushes
  • machine washing and drying clothes and linens that a person with head lice has used in the 2 days before lice treatment
  • avoiding contact with beds, couches, or other surfaces a person with head lice has recently used

According to the CDC, a person does not need to spray or fumigate the home. It does not effectively kill or prevent head lice and can have harmful effects on a person’s health.

Learn more about how lice spread.

Below are some common questions and answers about head lice and fleas.

Can humans get fleas?

Humans can get fleas, but dogs and cats are particularly vulnerable to them. Fleas can transmit to humans from pets.

Can fleas live in human hair?

Fleas can live on humans and consume their blood. This may include a person’s scalp or hair.

Can lice jump?

Lice cannot jump, but they can crawl from one person to another.

Head lice and fleas both cause itchy skin reactions in people who encounter them. Fleas may transmit disease to humans, but lice do not.

A person can treat both with medications to help manage symptoms of bites from the insects. People can also use medical treatments to kill lice. People with pets may need to treat them with medications from a veterinarian to kill fleas. Additionally, a person may need to thoroughly clean their home to remove fleas.

People can take steps to avoid both insects, for example, by regularly cleaning the home, limiting contact with stray animals, and washing clothes and linens regularly.