Pubic lice, also known as "crabs," are tiny parasitic insects that live in coarse human hair, primarily in the genital area. Their scientific name is Phthirus pubis. Though often associated with sexual activity, pubic lice can also spread through close personal contact or sharing personal items like towels and bedding.

Estimates suggest about 2% of adults may experience pubic lice, but this number is hard to verify since many people do not seek medical attention or even realize they are infested.

Understanding Pubic Lice: What Are They?

Pubic lice are different from head lice and body lice. While all are parasites that feed on human blood, pubic lice have a distinctive appearance, resembling miniature crabs under magnification. They latch onto coarse body hair and feed several times a day by piercing the skin.

Life Cycle of Pubic Lice

Pubic lice go through three main stages:

  • Eggs (Nits): These oval, yellowish-white eggs attach firmly to hair shafts near the skin. They hatch in about 6–10 days.

  • Nymphs: These immature lice hatch from the eggs and resemble smaller versions of adult lice. They mature into adults within 2–3 weeks.

  • Adults: Adult lice are tan or grayish-white and measure around 1–2 mm in length. They survive by feeding on blood and die within 24–48 hours if detached from the human body.

Symptoms of Pubic Lice

Symptoms usually appear around five days after exposure, although not everyone experiences noticeable symptoms. Common signs include:

  • Intense itching in the genital or affected area

  • Sensation of crawling insects on the skin

  • Visible lice or nits in pubic hair, often mistaken for dandruff or lint

  • Blue or red bite marks caused by louse feeding

  • Inflammation or secondary infection from scratching

Though most cases affect the genital area, lice can also infest armpits, chest hair, beard, eyebrows, and even eyelashes—especially in children. Lice in the scalp are usually head lice, not pubic lice.

How Do You Get Pubic Lice?

Pubic lice are most commonly spread through sexual contact. However, they can also spread via:

  • Sharing towels, bedding, or clothing with an infested person

  • Close nonsexual contact, though this is rare

  • Household transmission in cases of close living conditions

Unlike head lice, pubic lice don’t jump or fly—they crawl from hair to hair during direct contact. They don’t spread via toilet seats or animals.

Risk Factors

Certain factors increase your likelihood of contracting pubic lice:

  • Being sexually active, especially with multiple partners

  • Close contact with someone who has pubic lice

  • Sharing personal items like towels or underwear

  • Having other STIs, which increases your risk of exposure to additional infections

Diagnosing Pubic Lice

You may suspect you have pubic lice based on symptoms and visible signs. However, it's often difficult to identify lice without a magnifying glass.

If you’re unsure or your symptoms don’t resolve, visit a healthcare provider. Diagnosis typically involves:

  • Visual examination of affected areas

  • Use of magnification to detect lice and eggs

  • Assessment of sexual history or exposure

  • Testing for other STIs, which may occur alongside lice

In children, pubic lice in the eyebrows or eyelashes can indicate sexual abuse, though they can also spread via household contact.

How To Treat Pubic Lice

Treating pubic lice typically involves over-the-counter (OTC) or prescription medications and proper hygiene.

Medications

Effective treatments include:

  • 1% Permethrin lotion – Applied to the affected area and rinsed after 10 minutes

  • Pyrethrins with piperonyl butoxide – A mousse that also kills lice on contact

  • Topical ivermectin lotion – FDA-approved treatment (note: oral ivermectin is not approved for pubic lice)

If OTC treatments don’t work, your doctor may prescribe stronger medications.

Additional Steps

To fully get rid of pubic lice:

  • Remove all nits using a fine-toothed comb after treatment

  • Shave or trim affected hair to reduce lice habitat

  • Wash clothing, bedding, and towels in hot water (at least 130°F/54°C)

  • Dry items on high heat for at least 20 minutes

  • Seal non-washable items in plastic bags for two weeks to starve lice

  • Wear clean underwear and clothes after each treatment

  • Avoid sexual contact until treatment is complete

  • Inform recent sexual partners so they can be tested and treated if necessary

How To Prevent Pubic Lice

While pubic lice aren’t always preventable, especially if a partner is unknowingly infested, you can reduce your risk with these steps:

  • Avoid sexual contact with individuals who have lice

  • Don’t share towels, bedding, or undergarments

  • Wash items frequently if there's been known exposure

  • Screen new sexual partners, especially in high-risk environments

  • Educate yourself and your partners about lice symptoms and prevention

Potential Complications

While pubic lice don’t carry or transmit diseases, they can cause complications such as:

  • Skin infections from excessive scratching

  • Allergic reactions to louse bites

  • Secondary bacterial or fungal infections

  • Emotional stress, embarrassment, or relationship strain

Prompt treatment minimizes the risk of complications and limits the chance of spreading lice to others.

Living with Pubic Lice

It can be uncomfortable and distressing to have pubic lice, but the condition is treatable and manageable. Here are some important tips:

  • Don’t panic or feel ashamed—lice are common and don’t reflect poor hygiene

  • Follow treatment instructions carefully

  • Complete full treatment, even if symptoms improve

  • Monitor for recurrence, which may happen if nits survive or a partner is untreated

  • Recheck your body regularly for signs of lice or itching

  • Talk openly with partners to prevent reinfection

When To See a Doctor

Seek medical advice if:

  • OTC treatments fail or symptoms persist

  • You notice lice in your eyelashes or eyebrows

  • You're experiencing severe itching or secondary infections

  • You may have been exposed to other STIs

A doctor may also help rule out similar conditions such as scabies or eczema and can prescribe stronger medications if needed.

Final Thoughts

Pubic lice, or "crabs," are a common parasitic infection spread mainly through sexual contact. While they can be itchy and unpleasant, they are generally harmless and treatable with OTC or prescription medications.

Maintaining good hygiene, avoiding contact with infested individuals, and notifying sexual partners can prevent spread and recurrence. If you experience ongoing symptoms, don't hesitate to consult a healthcare provider.