What are lice?

Lice and fleas are tiny wingless insects that can infest humans and their homes.

Lice and fleas are tiny wingless insects that can infest humans and their homes.

Lice are tiny parasites that can infest the human skin and scalp. They are wingless insects that are about the size of a sesame seed. Infestation with lice is known as pediculosis and can occur on the head (head lice), body, or genital area (pubic lice). Different types of lice tend to infest the scalp, body, or genitals.

What are fleas?

Fleas, like lice, are small wingless insects. Unlike lice, which can only crawl, fleas can jump from one host (such as a pet) to another. Fleas mainly feed on non-human hosts but are able to infest humans. Lice can only live for a day or two without a host, but fleas may live for up to 100 days without a human or animal host. Fleas can live in fabrics and carpets in the home and may be carried by pets.

What are the signs and symptoms of lice and fleas?

Head lice symptoms

Head lice cause an intense itching or tickling feeling in the hair. It is usually worse at night when the lice are most active. The lice themselves may be visible, or you may recognize the nits (eggs) attached to hair shafts. On the body, lice also cause severe itching and may cause a red rash as an allergic reaction. If the lice have been present for some time, the skin may thicken or become dark. Pubic lice cause a similar reaction in the genital areas.

Fleabite symptoms

Fleabites may not produce a visible reaction in many people, so no symptoms may be apparent. In others, fleabites may appear as small bites with a central red spot on the skin. They may appear in groups or form a scab. Uncommonly, people may develop an allergic reaction to fleabites that includes skin swelling, irritation, and hives.

When to seek medical care for lice and fleas

Seek medical advice if you have symptoms suggestive of lice or fleabites and if home remedies or over-the-counter medications are ineffective.

What specialists treat lice and fleas?

Health care professionals who practice primary care — including family practitioners, internists, and pediatricians — typically treat lice and fleas. Sometimes dermatologists or skin specialists treat these conditions.

How do doctors diagnose lice and fleas?

Doctors diagnose a lice infestation by observing the skin directly and identifying the lice or their eggs. They diagnose fleabites typically by looking at the affected skin. Fleabites may sometimes be confused with bedbug bites, but bedbug bites may form blisters, while fleabites typically do not. No special tests are usually required for the diagnosis of lice or fleas.

What are treatments and home remedies for lice and fleas?

Body and head lice treatment

Body lice are usually managed by washing the body well along with any personal belongings that could be contaminated. There are a number of over-the-counter products available that kill head lice and pubic lice. Prescription medications are available if over-the-counter products are not effective.

Home remedies for fleas

Home remedies that may manage fleabites include over-the-counter cortisone creams, tea tree oil, calamine lotion, and vinegar. Antihistamine medications may be necessary for allergic reactions to fleabites.

What is the prognosis for lice and fleas?

Scratching or irritation of the affected areas can sometimes lead to complications like skin and soft tissue infections. However, lice infestations and fleabites are treatable and typically do not cause any long-term problems.

How to prevent lice and fleas

If someone has been infested with lice, it is important to de-contaminate personal belongings.

  • Wash bedding, towels, and clothing with hot, soapy water with a temperature of at least 130 F (54 C), and dry them on high heat for at least 20 minutes. 
  • Dry cleaning is also effective.
  • Seal non-washable materials in a plastic bag and store them in a warm area for two weeks.
  • Lice-killing sprays and other products are available for mattresses and furniture.

Prevent fleas by: 

  • Properly treating family pets with veterinarian-recommended anti-flea medications
  • Regularly cleaning and vacuuming furniture and floors
  • Regularly washing bedding and home textiles

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Medically Reviewed on 1/29/2020

References

Jameson, J. Larry, et al. Harrison’s Principles of Internal Medicine, 20th Edition. New York: McGraw-Hill Education, 2018.