Trigger warning: This article includes graphic and highly detailed photos of pubic lice infestations that some people may find upsetting. If you wish to proceed, do so with caution of the explicit imagery.

Pubic lice, often referred to as “crabs” due to their claw-like front legs, are small parasitic insects.³ Also known as “Phthirus pubis” by medical professionals, pubic lice are a different species from both head and body lice, and they do not inhabit the same areas of the body.² The ideal habitat for pubic lice is thick, coarse hairs, and as their name suggests, pubic lice commonly reside in the pubic region.² However, it is possible for the infestation to spread to other hairy parts of the body, including the underarm, eyelashes, eyebrows, or facial hair, such as beards and mustaches.³ The lice secure themselves to the base of human hairs, causing itchiness and irritation to the skin as the lice inhabit and feed on their human host. Treatment for pubic lice is relatively simple and can be done without a diagnosis or prescription from a doctor. Pubic lice infestations may affect people in all regions of the world, regardless of ethnicity, culture, and social or economic status.¹

Transmission

Pubic lice can be transmitted in several ways. Transmission commonly occurs through intimate physical contact, such as anal, vaginal, or oral sex, with a person infested with the lice.⁴ The reason for this transmission is that pubic lice commonly reside in the hair near the genitals, where the hair is thick and coarse, and the space between shafts of hair is ideal for them to grab on and feed.⁵ It is, however, still possible for individuals to become infested if their body hair comes into contact with any infested areas of the lice carrier.¹ 

Since they cannot survive without a human host for more than 24-48 hours, it is unlikely, but still possible, for pubic lice to be transmitted via infested clothing, bed linens, furniture, or towels.²  Pubic lice cannot jump or fly, and are not known to spread through quick, casual interactions such as a hug.³ Children may also become infested with pubic lice, which can be found in their eyelashes or eyebrows. This can be a sign of sexual abuse or exposure, although it is possible that transmission could also occur through infested clothing, bedding, or towels.³

Once pubic lice are contracted and an insect is secured onto the body, adult female lice lay their eggs, called “nits,” in a cluster near the base of hair shafts.¹ These female lice may lay up to 10 eggs per day during their 1-2 month lifespan.² The eggs are typically oval shaped and range from white to yellow in color.¹ Due to a thick, sticky substance, the eggs are able to stay put for the week that it takes them to develop into their next stage of life.¹ Because of their stickiness, nits are able to survive on materials or surfaces, without a human host, for up to a week.⁵ Once they hatch, the nits are considered “nymphs,” or immature lice, which then feed on human blood and continue with the lice cycle of life.¹ 

Symptoms

The symptoms of pubic lice often do not vary among people of different genders. The primary symptom of pubic lice is a persistent itch, caused by a physical, allergic reaction to the saliva from the bites of the lice, which may intensify at night when lice are more active.⁴ Other common symptoms include inflammation, rash, blue spots, or spots of blood visible at the site of bites

Adult lice may range anywhere from 1.5 to 2 mm in length, have flat bodies, and can be greyish-white to reddish-brown in color depending on how recently they’ve eaten.¹ Due to their incredibly small size, and coloring that can blend into different skin tones, pubic lice and nits may be visible, but hard to see, near the base of hair shafts. 

Some individuals have pubic lice, but are asymptomatic; meaning that they have no symptoms. This can occur when individuals misattribute the rash to a different source.¹ Individuals can also appear to be asymptomatic due to how difficult it can be to see the lice, especially when located in the pubic region. A magnifying glass can be used to see lice and nits more closely, or a medical professional may be consulted to check for lice under a microscope. 

Despite their annoyance and discomfort, pubic lice are not known to be carriers of bacterial or viral diseases. However, it is possible for them to cause a secondary bacterial infection due to excessive scratching of the skin, which may cause abrasions, leaving the skin vulnerable to bacteria and infection.¹  If lice infect an individual’s eyebrows or eyelashes, these areas may become inflamed and it is even possible for them to develop conjunctivitis, an infection also known as “pink eye”.⁴ Generally, the symptoms of pubic lice become apparent approximately 5 days after transmission.³

Treatment

Pubic lice and nits are not killed or removed from hair with ordinary soap and water, so a special treatment is necessary. The treatments range from lotions to mousses, shampoos, and more.³ It is recommended to use a lotion containing 1% permethrin or a mousse with pyrethrins and piperonyl butoxide.¹ A single treatment is meant to be powerful enough to stop an infestation, but it is sometimes suggested to repeat the treatment after one week to kill any eggs that might have hatched into lice after the first attempt to kill them.⁴ It is not, however, recommended to use treatments more than twice.⁴ These lice killing treatments are available online and at most local drugstores and pharmacies without a prescription.³ They can be incredibly safe and effective when used properly, so careful examination of the directions is highly recommended, since this should be treated similarly to any other form of medication.¹ 

If lice have infested hair on the face, especially the eyelashes or eyebrows, insecticide treatments such as permethrin should not be used on these areas.¹ Instead, lice should be removed manually, using tweezers or a fine-toothed brush to comb or pick them out.¹ It is also possible to contact a healthcare provider for additional treatment, whether it is to ensure the correct diagnosis, or to be provided with a more effective, alternative treatment method while under doctor supervision. 

If an infected person has found themselves allergic or intolerant to the first line treatment of permethrin, a doctor may prescribe lindane shampoo as a second line treatment.¹ This medication can be toxic to the brain and can pose other threats to the nervous system.¹ It should not be used to treat patients with high risk conditions, such as cancer and seizures, and patients who are infants, children, elderly, under 110 lbs., pregnant, breastfeeding, experience sensitivity to the treatment, or have a negative skin reaction to the product.¹ 

Once the chemical treatment has been completed, the lice and eggs will usually have to be combed, tweezed, or picked using fingernails, out of the infected region.¹ The next step in eliminating the pubic lice infestation is to machine wash, at a hot temperature, all clothing, towels, bed linens, and other objects that the infected person was exposed to between 2 and 3 days before treatment.³ They should also be dried at a high temperature of at least 130°F (54°F) and for a period of at least 20 minutes in order to prevent re-infestation.¹ Any items that cannot be treated using a machine washer and dryer should be dry cleaned, or sealed in a plastic bag for a minimum of two weeks, to allow time for the pubic lice to perish without a host to thrive on.¹ Fumigation using chemical fogs are an unnecessary method of eradication for pubic lice and pose unnecessary risks to humans if inhaled or absorbed through skin contact.¹

Prevention

To prevent infestations of pubic lice, an infested person should contact intimate, sexual partners or people they have shared linens, towels, or clothing with during the previous 30 days to inform them of their lice infestation.¹ This will allow their partners to determine whether or not they have also become infested, and seek medical attention and treatment before it is transmitted further. 

Maintaining pubic hair can be a major factor in limiting the spread of pubic lice.⁵ The lice and eggs live on coarse hair and therefore hair removal, whether it be shaving or waxing, can reduce the transmission and infestation of pubic lice.⁵ Another way to control the transmission of pubic lice is to regularly wash and dry clothing, bedding, and other material objects that could become infested at a high temperature.¹

Although condoms provide protection against most sexually transmitted infections, they do not protect against pubic lice.³ Since they are transmitted through direct physical contact of hairy regions that are unable to be covered, it is difficult to prevent pubic lice transmission if an individual is sexually active.³ It is best for individuals to communicate with their partner about STIs and sexual health, and to conduct self-exams. If any drastic changes are noticed in the genital region, individuals should contact a medical professional.

Concluding Remarks

Pubic lice are a relatively contagious, and common sexually transmitted infection that occur worldwide, and infest people at every level of society.³ Proper hygiene can help to prevent and limit the spread of infestation. However, having pubic lice does not mean that an individual is dirty or unhygienic.¹ In the United States, pubic lice affects 3 million people each year, while the percentage of individuals who experience infestations worldwide are estimated to be approximately 2%.³ Although this data has remained consistent over the past few years, it has been theorized that the prevalence of pubic lice is falling, especially in more highly developed countries, due to pubic grooming practices that eliminate the ideal environment of pubic lice.⁵ Despite the discomfort of such an infestation, and the inconvenience of managing and eradicating it, pubic lice is one of the only sexually transmitted infections or diseases that may be self-diagnosed, as well as self-treated. However, guidance from a trained medical professional is recommended for individuals who are pregnant, have a skin infection from scratching, or notice that at-home products did not work.⁶ It is crucial to inform those who have had intimate contact with the affected person of their condition so that they too can seek treatment, and avoid additional contact until the infestation is fully eradicated.¹

References:

1. “Pubic ‘Crab’ Lice.” Web. Center for Disease Control, 2019.
2. “Pubic Lice.” Web. National Health Service, 2018. 
3. “Pubic Lice (Crabs).” Web. Planned Parenthood, 2020.
4. “Pubic Lice (Crabs).” Web. Mayo Clinic, 2018.
5. LeVay, Simon, et al. “Sexually Transmitted Infections” Discovering Human Sexuality, 4th ed. Print. 2019.
6. Greenberg, Jerrold S., et al. “Sexually Transmitted Infections.” Exploring the Dimensions of Human Sexuality, 6th ed. Print. 2017.

Last Updated: 02 June 2020