Crab lice: causes and treatment of pubic lice

By Cristiano Antonino Last updated Jun 6, 2023

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Crab lice, or pubic lice, are very small insects that infest the genital area. Typically, they live on pubic hair and are spread through intimate or sexual contact

In rarer cases they make their way into eyelashes, eyebrows, armpit hair, facial hair and other hair.

In all cases, they feed on human blood and cause intense itching in the affected areas.

Typically, crab lice are smaller than the more well-known head and body lice.

Pubic lice infestations are more common among people who have sexually transmitted infections.

Crab lice

Pubic lice, better known as crab lice, are small parasitic insects that can settle in areas of the body covered in hair.

In most cases, they are located in the pubis, but they can also affect the eyelashes, eyebrows, armpits, beard, back, abdomen, chest, legs, mustache.

The only area spared is that of the hair, which can however be affected by head lice.

Adult lice are very small (about two mm long) and are not easy to see. They are yellow-gray or dark red in color and have six legs.

They are sometimes called crabs because they have two large front legs that look like the claws of a crab: they are used to hold the base of the hairs.

Lice lay their eggs (called nits) in “sacks” that are tightly attached to hair and are pale brownish in color.

When the eggs hatch, the empty egg sacs turn white.

Although lice and lice eggs are small and hard to see, they can technically be visible in coarse hair anywhere on the body.

Causes of pubic lice

Pubic lice, just like head lice, are not related to poor personal hygiene, as a false myth has it.

Usually, they are spread through close bodily contact with an infected person.

Lice crawl from hair to hair, but they cannot fly or jump.

They need human blood to survive, so they will only leave the body to move from one person to another.

The most common way lice are spread is through sexual contact, including vaginal, anal, and oral sex.

Unfortunately, the use of condoms and other barrier methods of contraception do not protect against head lice.

Other types of close body contact, such as hugging and kissing, can also spread lice.

It’s also possible, though much rarer, for lice to be spread by sharing clothes, towels, and bedding.

Not infrequently, crabs affect people who are already affected by sexually transmitted diseases.

Pubic lice symptoms

People with pubic lice often experience itching in the genital and/or anal region starting about five days after the initial infestation.

At night, the itching tends to become more intense.

Other common head lice symptoms include:

low fever
irritability
lack of energy
pale bluish spots near the bites

Excessive itching can cause wounds or an infection in the affected areas.

Children with lice infestations on their eyelashes are at risk of developing conjunctivitis.

How are crabs transmitted?

As anticipated above, crabs are typically transmitted through close intimate contact and sexual intercourse.

It’s also possible to get infected by using the blankets, towels, bedding, or clothing of people who have bed bugs.

Contrary to common belief, it is highly unlikely to become infested through the use of the same bathroom or piece of furniture with an infested person.

Pubic lice usually don’t fall off their host unless they are dead.

They also cannot jump from person to person like fleas.

Adult lice lay their eggs on the hair shaft close to the skin.

Seven to 10 days later, the nits hatch into nymphs, which begin feeding on the blood.

Lice can live without their food supply for a day or two.

Children can get an infestation after sleeping in the same bed as someone who has louses.

Genital crabs diagnosis

Your doctor can easily diagnose crabs based on describing your symptoms and doing a physical exam.

The person can also become aware of the presence of lice by examining their pubic area thoroughly.

If you suspect an infestation, but can’t see well with the naked eye, you can use a magnifying glass.

Lice are usually light gray in color, but may darken after drinking blood.

If you notice tiny crab-like bugs moving between your pubic hair then you likely have an infestation.

The eggs are small and white and usually found around the roots of pubic hair or other body hair.

Crab lice: the cures

Treatment of crabs consists of a decontamination of the genital area, clothes and bedding.

To remove lice from the body you can use over-the-counter topical creams, lotions or shampoos, based on pesticides.

The ideal is to rely on the advice of your doctor to understand which product is best to use and to know how to proceed.

This recommendation is even more valid for particular cases, such as pregnancy and breastfeeding and in the case of children.

Obviously it is also important to read the product instructions well to understand exactly the quantity to use, the processing time and the frequency of use.

Not infrequently, a second application may be required after a few days.

You may also need prescription medications if topical solutions don’t work.

For eyelash lice, be even more careful: the doctor will recommend the most suitable medicines for the eye area.

Do not use regular lice shampoos around the eyes.