Pubic Lice (Crabs): Symptoms, Treatment, and Prevention

Pubic Lice (Crabs): Symptoms, Treatment, and Prevention

Feature	Pubic Lice (Crabs)	Similar problem	Best next step
Main clue	Look for the traits described in this guide, then confirm with direct evidence.	Compare size, behavior, location, and damage before choosing treatment.	Match your control method to the pest you can verify.
Common mistake	Acting on one sign alone.	Assuming the same tools work equally well for both.	Inspect droppings, entry points, and activity areas together.
Control impact	Requires the method, placement, and follow-up timing that fit Pubic Lice (Crabs).	Requires the method, placement, and follow-up timing that fit Similar problem.	Recheck results after several nights and adjust if signs continue.

Pubic lice, scientifically known as Pthirus pubis and commonly called "crabs," are a distinct species of louse that infests coarse body hair. Unlike head lice and body lice, pubic lice are a separate species with a shorter, rounder body shape that resembles a tiny crab, which is how they earned their common name.

While pubic lice infestations have declined significantly in recent decades, they remain a concern and are typically classified as a sexually transmitted infestation.

What Are Pubic Lice?

Pubic lice are small parasitic insects that primarily infest the pubic region. They measure about 1.1 to 1.8 millimeters, making them smaller than head lice. Their body is broader and flatter, with large front claws adapted to gripping coarse hair. Understanding what lice look like can help you identify the differences between lice species.

Pubic lice can also be found in other areas with coarse hair, including armpits, chest hair, beards, eyebrows, and eyelashes.

How Do You Get Pubic Lice?

Pubic lice are most commonly transmitted through sexual contact. They crawl from the body hair of one person to another during close physical contact. Less commonly, they can spread through shared towels, bedding, or clothing, though this route is rare because lice cannot survive long away from the body.

Like all lice, pubic lice cannot jump or fly. They can only crawl.

Pubic lice cannot live on pets, as they are strictly human parasites.

Symptoms

Lice symptoms from pubic lice include:

• Intense itching in the pubic area, usually worse at night
• Visible lice or nits on pubic hair
• Small blue-gray spots (maculae ceruleae) on the skin where lice have been feeding
• Lice bites that appear as small red dots
• Dark or rust-colored powder in underwear from lice droppings

Symptoms typically appear about 5 days after initial infestation, though some people may not notice symptoms for several weeks.

Treatment

Over-the-Counter Options

Lice shampoo products containing pyrethrins or permethrin can be applied to the affected area. Follow the product instructions carefully and apply to all areas of coarse body hair where lice may be present.

Prescription Treatments

For resistant cases, a doctor may prescribe ivermectin or stronger topical treatments. This is especially relevant given the rise of treatment-resistant lice.

Eyelash and Eyebrow Infestations

Pubic lice that have spread to the eyelashes or eyebrows require special treatment. Standard lice shampoos should not be used near the eyes. A doctor may prescribe ophthalmic-grade petroleum jelly or other specialized treatments.

Partner Notification

Sexual partners from the past month should be notified and treated simultaneously to prevent reinfestation. All household members should be checked.

Environmental Cleaning

Wash bedding and recently worn clothing in hot water and dry on high heat. Avoid sharing towels or bedding during treatment. Follow our guide on how to clean house after lice for a complete cleaning protocol.

Risk and Severity

Pubic lice pose risks beyond the discomfort of itching. Because they are classified as a sexually transmitted infestation, a diagnosis warrants consideration of screening for other sexually transmitted infections, since risk factors overlap. Intense itching in the pubic area leads to scratching that can introduce bacterial skin infections. The small blue-gray skin discolorations (maculae ceruleae) at bite sites are harmless but can cause alarm. Delayed diagnosis is a specific risk: symptoms typically begin 5 days after infestation but can be absent for several weeks in first-time cases, allowing spread to additional partners during the asymptomatic period. If pubic lice spread to the eyelashes or eyebrows, specialized treatment from a healthcare provider is required; standard lice shampoos should not be used near the eyes.

Prevention

Pubic lice are transmitted primarily through sexual contact, so prevention follows the same approach as other sexually transmitted infections. Barrier protection during sexual contact reduces but does not eliminate transmission risk, since lice can infest areas not covered by barriers. Avoid sharing towels, bedding, and clothing with anyone who has an active infestation. If exposure is suspected, inspect the pubic hair and coarse body hair and seek evaluation promptly. All sexual partners from the past month should be notified and treated simultaneously to prevent reinfestation. Wash bedding and recently worn clothing in hot water and dry on high heat. See our lice prevention guide for additional strategies.

For comprehensive information on all lice types, visit our complete guide to lice.

The Decline of Pubic Lice

An interesting epidemiological trend is the decline of pubic lice infestations in many countries over the past two decades. Researchers have linked this decline to the increasing popularity of pubic hair removal through shaving, waxing, and laser treatment. Without their preferred habitat, pubic lice populations have diminished significantly.

However, pubic lice have not disappeared entirely. They continue to affect individuals who maintain pubic hair and can also infest other coarse body hair including underarm hair, chest hair, beards, and facial hair around the eyebrows and eyelashes.

Pubic Lice vs Head Lice

Pubic lice and head lice are different species with distinct characteristics:

• Body shape: Pubic lice are shorter and rounder; head lice are elongated
• Claw structure: Pubic lice have larger front claws adapted to coarser hair
• Speed: Pubic lice move more slowly than head lice
• Habitat: Pubic lice prefer coarse body hair; head lice prefer scalp hair
• Transmission: Pubic lice are primarily sexually transmitted; head lice spread through head-to-head contact
• Species: Pubic lice (Pthirus pubis) are a different genus than head lice (Pediculus humanus)

Diagnosis Considerations

Because pubic lice can mimic other conditions, proper diagnosis is important. Conditions that may be confused with pubic lice include:

• Folliculitis (infected hair follicles)
• Contact dermatitis
• Eczema
• Fungal infections
• Other sexually transmitted infections

A healthcare provider can confirm the diagnosis by examining the affected area for live lice or nits. If pubic lice are diagnosed, screening for other sexually transmitted infections is often recommended since risk factors overlap.

Emotional and Relational Considerations

A pubic lice diagnosis can cause significant emotional distress, including embarrassment, anxiety, and relationship tension. It is important to remember that:

• Pubic lice are treatable and temporary
• They do not indicate infidelity (they can have long incubation periods)
• Open communication with partners facilitates treatment and prevents reinfestation
• Healthcare providers treat pubic lice regularly and without judgment

Expert Insight

While my IPM consulting work focuses primarily on head lice in school settings, I occasionally receive questions from parents about pubic lice, particularly regarding how they differ from head lice and whether cross-contamination is possible. In 15 years of practice, I have learned that clear education about the different lice species helps families understand their specific situation. Pubic lice are a separate species with different transmission patterns and treatment considerations that should be discussed with a healthcare provider.

-- Sarah Mitchell, Board Certified Entomologist (BCE), 15 years in Integrated Pest Management

References and Sources

• CDC - Pubic Lice Information
• Mayo Clinic - Pubic Lice
• NIH - Pthirus pubis
• Harvard Health - Pubic Lice Overview

Main Causes

Head lice spread overwhelmingly through direct head-to-head contact. Shared combs, brushes, hats, helmets, headphones, pillows, and upholstered furniture used within a day or two by an infested person occasionally transmit, but contact remains the dominant route. Schools, daycares, sleepovers, sports teams, and family groups account for the majority of cases. Body lice, by contrast, live in the seams of clothing and bedding rather than on skin, and are associated with limited access to laundering rather than with personal hygiene. Pubic lice spread through close intimate contact. Hair length, hair texture, and cleanliness do not influence susceptibility to head lice — the parasites cling to clean hair as easily as unwashed hair.

How to Identify

Reliable identification requires a wet comb examination rather than a visual scan. Saturate the hair with conditioner, then draw a fine-toothed metal lice comb from scalp to tip in small sections, wiping the comb on a white paper towel after each pass and inspecting under good light. Adult lice are two to three millimeters long, tan to grayish-white, and move quickly. Nits are pinhead-sized cream-yellow ovals cemented to the hair shaft within a quarter inch of the scalp; they do not slide off when pushed, distinguishing them from dandruff and product residue. Itching may be absent for the first four to six weeks of an infestation, so combing rather than waiting for symptoms is the proper diagnostic step.

Solutions and Actions

Eliminate head lice through a treat-and-comb protocol rather than any single application. Apply a pediculicide labeled for head lice (over-the-counter permethrin or pyrethrin products are first-line; prescription options exist for treatment-resistant cases). Critically, repeat the application at seven to ten days to catch nymphs that hatched from eggs surviving the first treatment — skipping this second application is the most common reason treatments fail. Combine medication with daily wet combing using a fine-toothed metal lice comb, applying conditioner and combing in sections, for at least two weeks. Wash and dry recently used bedding and clothing on high heat. Bag stuffed animals and headgear that cannot be washed for two weeks. Check all household members on the same day and treat anyone positive.

Frequently Asked Questions

Are pubic lice the same as head lice?

No. Pubic lice (Pthirus pubis) are a completely different species from head lice (Pediculus humanus capitis). They are smaller, have a rounder body shape, and prefer coarse body hair rather than scalp hair. The two species have different transmission patterns and are treated differently.

Can pubic lice spread to the head?

Pubic lice strongly prefer coarse body hair and rarely infest the scalp. However, they can occasionally spread to other areas with coarse hair, including eyebrows, eyelashes, chest hair, and armpit hair. The fine texture of scalp hair is generally not suitable for pubic lice.

How are pubic lice treated?

Pubic lice are typically treated with permethrin cream or pyrethrin-based products applied to the affected area. All sexual partners from the past month should also be treated. Bedding and clothing should be washed in hot water. For lice in eyebrows or eyelashes, special treatment under medical supervision is required.

Are pubic lice becoming less common?

Some research suggests that pubic lice infestations have declined in recent decades, possibly related to changes in personal grooming practices. However, they remain a recognized sexually transmitted condition that requires proper diagnosis and treatment.