What are pubic lice and how are they spread. How can you identify and treat pubic lice infestations. What are effective prevention methods for avoiding pubic lice. How do pubic lice differ from other types of lice.

Understanding Pubic Lice: An Overview of the “Crabs” Infestation

Pubic lice, colloquially known as “crabs,” are tiny parasitic insects that infest the coarse body hair of humans, primarily in the pubic region. These minuscule creatures, measuring about 2mm in length, have a grey-brown coloration that makes them challenging to spot with the naked eye. While they predominantly inhabit pubic hair, these lice can also be found in other areas with coarse hair, such as the chest, armpits, facial hair, and even eyelashes.

Unlike their cousins – head lice and body lice – pubic lice are specifically adapted to the coarser hair found in the genital area. They rely on human blood for survival, attaching themselves to hair shafts and feeding on the host’s blood. This parasitic relationship can lead to various uncomfortable symptoms and potential health concerns if left untreated.

Characteristics of Pubic Lice

• Size: Approximately 2mm long
• Color: Grey-brown
• Preferred habitat: Coarse body hair, especially in the pubic region
• Feeding habit: Survives on human blood
• Mobility: Can only crawl; unable to hop or fly

Are pubic lice visible to the human eye? While pubic lice are indeed visible, their small size and coloration make them difficult to spot without close inspection. Often, the first indication of their presence is the appearance of symptoms rather than visual confirmation of the lice themselves.

Identifying Pubic Lice: Signs and Symptoms to Watch For

Recognizing the signs and symptoms of a pubic lice infestation is crucial for early detection and treatment. While the lice themselves may be hard to spot, their presence often manifests through various physical indicators and discomfort.

Common Symptoms of Pubic Lice Infestation

• Intense itching, particularly in the pubic area
• Small red or blue spots on the skin (lice bites)
• Visible lice eggs (nits) attached to hair shafts
• Dark red or brown spots in underwear (lice feces)
• Crusted or sticky eyelashes (if eyelashes are affected)

Is itching always present with pubic lice infestations? While itching is the most common symptom, it’s important to note that not everyone experiences intense itching immediately. Some individuals may have a mild infestation for weeks before noticing significant discomfort.

Can pubic lice infest areas other than the pubic region? Yes, although less common, pubic lice can also inhabit other areas with coarse hair, including the chest, armpits, beard, eyebrows, and even eyelashes. In children or adolescents, the presence of pubic lice on eyebrows or eyelashes may indicate sexual exposure or abuse, warranting further investigation.

Transmission and Spread: How Pubic Lice Move from Person to Person

Understanding how pubic lice spread is essential for both prevention and determining potential exposure. Unlike some other parasites, pubic lice have specific modes of transmission that are primarily related to close physical contact.

Primary Methods of Transmission

1. Sexual contact: The most common method of transmission
2. Close body contact: Non-sexual skin-to-skin contact in infested areas
3. Shared personal items: Rarely, through clothing, bedding, or towels used by an infested person

Do pubic lice jump or fly between hosts? No, pubic lice cannot jump or fly. They can only crawl, which is why close physical contact is necessary for transmission. This limitation in mobility is one of the key factors that differentiate pubic lice from other types of lice.

Can you get pubic lice from toilet seats? The risk of contracting pubic lice from toilet seats is extremely low. These parasites cannot survive long away from a human host and do not have the ability to grip smooth surfaces like toilet seats effectively.

Diagnosis and Treatment: Effective Approaches to Eliminating Pubic Lice

Proper diagnosis and treatment of pubic lice are crucial for eliminating the infestation and preventing its spread to others. While over-the-counter treatments are available, consulting a healthcare professional is often recommended, especially for first-time infections or cases where self-treatment has been ineffective.

Diagnostic Process

• Visual inspection of affected areas
• Use of magnifying lens to identify lice or nits
• Combing through hair to collect specimens for examination

Treatment Options

1. Over-the-counter medications: Permethrin 1% cream or pyrethrin-based shampoos
2. Prescription medications: Malathion 0.5% lotion or ivermectin pills for resistant cases
3. Manual removal: Combing out lice and nits with a fine-toothed comb

How long does treatment for pubic lice typically take? Most treatments require an initial application followed by a second treatment 7-9 days later to ensure all lice and newly hatched nymphs are eliminated. The entire process, including follow-up, usually takes about two weeks.

Is it necessary to treat sexual partners? Yes, it’s crucial to inform and treat all sexual partners from the past month to prevent reinfestation and further spread of the lice.

Prevention Strategies: Minimizing the Risk of Pubic Lice Infestation

While completely preventing exposure to pubic lice can be challenging, especially for sexually active individuals, there are several strategies that can significantly reduce the risk of infestation.

Effective Prevention Methods

• Practice safe sex and limit the number of sexual partners
• Avoid sharing personal items like clothing, towels, or bedding
• Regularly inspect the pubic area for signs of infestation
• Maintain good personal hygiene
• Wash and dry clothes and bedding at high temperatures (at least 50°C) if infestation is suspected

Do condoms prevent the transmission of pubic lice? While condoms are essential for preventing many sexually transmitted infections, they do not provide complete protection against pubic lice. These parasites can live on hair in areas not covered by condoms.

How can you prevent reinfestation after treatment? To prevent reinfestation, it’s crucial to thoroughly clean and treat the environment. This includes washing all clothing, bedding, and towels used in the past week in hot water and drying them on high heat. Items that can’t be washed should be sealed in plastic bags for at least two weeks.

Pubic Lice vs. Other Types of Lice: Understanding the Differences

While pubic lice share some similarities with other types of lice that infest humans, there are distinct differences in their characteristics, habitat preferences, and transmission methods. Understanding these differences is crucial for proper identification and treatment.

Comparison of Lice Types

Can one type of lice infestation lead to another? Generally, having one type of lice does not increase the likelihood of getting another type. Each species of lice is adapted to specific areas of the human body and doesn’t typically migrate to other regions.

Are treatment methods the same for all types of lice? While there are some overlaps in treatment approaches, such as the use of permethrin-based products, the specific applications and precautions may differ. For instance, treatments for pubic lice often need to be applied to a larger body area compared to those for head lice.

Pubic Lice and Sexual Health: Implications and Associated Risks

The presence of pubic lice can have broader implications for sexual health beyond the immediate discomfort and inconvenience of the infestation. Understanding these implications is crucial for comprehensive sexual health management.

Sexual Health Considerations

• Indicator of sexual contact: Pubic lice infestation often indicates recent sexual activity with an infested partner
• Potential co-infections: May signal the presence of other sexually transmitted infections (STIs)
• Psychological impact: Can cause embarrassment and anxiety, potentially affecting sexual relationships
• Partner notification: Necessity to inform recent sexual partners for treatment and prevention of spread

Does having pubic lice mean you have other STIs? While pubic lice infestation doesn’t directly cause other STIs, it can be an indicator of sexual contact that may have exposed you to other infections. It’s often recommended to undergo comprehensive STI testing when diagnosed with pubic lice.

How soon after sexual contact can pubic lice symptoms appear? Symptoms of pubic lice infestation typically appear within 5 to 7 days after exposure. However, if it’s a person’s first time being infested, it may take up to 2-3 weeks for noticeable symptoms to develop.

Myths and Misconceptions: Debunking Common Beliefs About Pubic Lice

Despite the prevalence of pubic lice infestations, there are numerous myths and misconceptions surrounding this condition. Addressing these misconceptions is crucial for promoting accurate understanding and effective prevention and treatment strategies.

Common Myths About Pubic Lice

1. Myth: Pubic lice can jump or fly between hosts
   Reality: Pubic lice can only crawl and require close contact for transmission
2. Myth: Only people with poor hygiene get pubic lice
   Reality: Pubic lice can infest anyone, regardless of personal hygiene habits
3. Myth: You can get pubic lice from toilet seats
   Reality: The risk of transmission from toilet seats is extremely low
4. Myth: Shaving pubic hair prevents lice infestation
   Reality: While it may make detection easier, shaving doesn’t prevent infestation
5. Myth: Pubic lice can transmit HIV or other serious diseases
   Reality: Pubic lice do not transmit HIV or other bloodborne pathogens

Can pets transmit pubic lice to humans? No, pubic lice are species-specific and cannot survive on pets. The lice that sometimes infest pets are different species and do not infest humans.

Is it possible to develop immunity to pubic lice after an infestation? Unfortunately, there is no evidence to suggest that humans can develop immunity to pubic lice. Each exposure can result in a new infestation if preventive measures are not taken.

In conclusion, understanding the facts about pubic lice is crucial for effective prevention, diagnosis, and treatment. By dispelling myths and promoting accurate information, we can better address this common but often misunderstood condition. Remember, if you suspect a pubic lice infestation, it’s important to seek medical advice for proper diagnosis and treatment, as well as to consider comprehensive sexual health screening.

Pubic lice – NHS

Pubic lice are tiny insects that can live on body hair, especially the pubic hair around the penis or vagina. They’re spread through close body contact, most commonly through sexual contact.

Pubic lice are sometimes also called crabs.

Check if you have pubic lice

Pubic lice are very small (2mm long) and grey-brown in colour.

They can be hard to spot, but sometimes you may be able to see them in your hair.

They most often live on pubic hair around the penis or vagina, but can also be found in hair on the chest, armpits, face and eyelashes. They do not affect hair on the head.

Other symptoms of pubic lice include:

• itching, which is usually worse at night
• small red or blue spots on your skin (lice bites)
• white/yellow dots attached to your hair (lice eggs)
• dark red or brown spots in your underwear (lice poo)
• crusted or sticky eyelashes, if they’re affected

Non-urgent advice: Go to a sexual health clinic or see a GP if:

• you think you might have pubic lice

Pubic lice will not go away without treatment.

If you’re sure you have pubic lice, you may be able to get treatment from a pharmacist.

What happens at your appointment

If you go to a sexual health clinic or GP surgery because you think you have pubic lice, a doctor or nurse will check your hair for lice.

They may check your pubic hair around your penis or vagina and any other areas that could be affected, such as your armpits, chest or eyelashes.

To help spot any lice, they might use a comb and a magnifying lens.

If they think you might have caught the lice during sex, they may ask about your sexual partners. They may also suggest getting tested for any sexually transmitted infections (STIs).

Treatment for pubic lice

The main treatments for pubic lice are medicated creams or shampoos that kill the lice.

You usually need to use the treatment on your whole body and leave it on for a few hours before washing it off. You’ll need to repeat this again a week later to make sure all the lice have been killed.

You may be asked to come back a week after you finish treatment, to check if the treatment has worked.

Any current or recent sexual partners should also be treated, even if they do not have symptoms.

How to stop pubic lice spreading

While you’re being treated for pubic lice, there are some things you can do to help stop the lice spreading to others and stop the lice coming back.

Do

• wash your clothes and bedding on a hot wash (50C or higher), get them dry cleaned, or put them in a plastic bag for at least a week – this will help kill any lice

• vacuum your mattress to remove any lice

How you get pubic lice

Pubic lice are mainly spread by close body contact, most commonly sexual contact.

The lice cannot jump or fly, but can climb from one person to another.

You can also catch the lice from clothes, bedding or towels used by someone with pubic lice, but this is rare.

How to avoid getting pubic lice

It can be hard to prevent pubic lice.

The only way to avoid getting them is to avoid having sexual contact (or sharing bedding or clothing) with anyone you know who has pubic lice, until they’ve been treated.

Condoms and other forms of contraception will not protect you from pubic lice. But it’s still a good idea to use condoms during sex because they reduce the risk of sexually transmitted infections (STIs).

Page last reviewed: 24 May 2022
Next review due: 24 May 2025

Pubic Lice | Crabs | MedlinePlus

What are pubic lice?

Pubic lice (also called crabs) are tiny insects which usually live in the pubic or genital area of humans. They are also sometimes found on other coarse body hair, such as hair on the legs, armpits, mustache, beard, eyebrows, or eyelashes. Pubic lice on the eyebrows or eyelashes of children or teens may be a sign of sexual exposure or abuse.

Pubic lice are parasites, and they need to feed on human blood to survive. They are one of the three types of lice that live on humans. The other two types are head lice and body lice. Each type of lice is different, and getting one type does not mean that you will get another type.

How do pubic lice spread?

Pubic lice move by crawling, because they cannot hop or fly. They usually spread through sexual contact. Occasionally, they may spread through physical contact with a person who has pubic lice, or through contact with clothing, beds, bed linens, or towels that were used by a person with pubic lice. You cannot get pubic lice from animals.

Who is at risk for pubic lice?

Since they spread mainly through sexual contact, pubic lice are most common in adults.

What are the symptoms of pubic lice?

The most common symptom of pubic lice is intense itching in the genital area. You may also see nits (lice eggs) or crawling lice.

How do you know if you have pubic lice?

A diagnosis of a pubic lice usually comes from seeing a louse or nit. But lice and nits can be difficult to find because there may be only a few present. Also, they often attach themselves to more than one hair, and they do not crawl as quickly as head and body lice. Sometimes it takes a magnifying lens to see the lice or nits.

People who have pubic lice should also be checked for other sexually transmitted diseases, and their sexual partners should also be checked for pubic lice.

What are the treatments for pubic lice?

The main treatment for pubic lice is a lice-killing lotion. Options include a lotion that contains permethrin or a mousse containing pyrethrins and piperonyl butoxide. These products are available over-the-counter without a prescription. They are safe and effective when you use them according to the instructions. Usually one treatment will get rid of the lice. If not, you may need another treatment after 9-10 days.

There are other lice-killing medicines that are available with a prescription from your health care provider.

You should also wash your clothes, bedding, and towels with hot water, and dry them using the hot cycle of the dryer.

Centers for Disease Control and Prevention

• Pubic “Crab” Lice Diagnosis

  (Centers for Disease Control and Prevention)

• Pubic “Crab” Lice Prevention and Control

  (Centers for Disease Control and Prevention)

• Pubic “Crab” Lice Treatment

  (Centers for Disease Control and Prevention)

• Pubic Lice (Crabs)

  (Mayo Foundation for Medical Education and Research)

  Also in Spanish

• Pubic Lice (Crabs) (For Teens)

  (Nemours Foundation)

  Also in Spanish

• Pubic Lice (For Parents)

  (Nemours Foundation)

  Also in Spanish

• Pubic Lice (Pediculosis Pubis)

  (VisualDX)

• Article: Dermoscopy of pediculosis pubis in an octogenarian man.

• Article: Secondary structure construction and molecular identification of rRNA 18S V4 region…

• Article: Lice and lice-borne diseases in humans in Africa: A narrative review.

• Pubic Lice — see more articles

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The crab test is the determination of IgE antibodies to the corresponding allergen.

Crabs are crustaceans that live in salty sea water (although there are species that live in fresh water). They are covered with a thick exoskeleton, have ten legs and one pair of claws. Snow crabs (Chionoecetes opilio) are the most widely used species from the Oreoniidae family.

Crabs are one of the most popular crustaceans consumed by humans, accounting for one fifth of all marine crustaceans caught, farmed and consumed worldwide. Crab meat is valued for its soft, tender and sweet taste. A distinction is made between white crab meat, which is obtained from claws and legs, and brown crab meat, which is obtained from the body. White meat has less fat, but brown meat has more omega-3 fatty acids. The orange or yellow eggs of the female crab can also be eaten.

The preparation of crabs for eating differs from region to region. Some species are eaten whole, while others only use certain parts, such as the claws. Imitation crab, also called surimi, is made from minced fish that has been processed and colored to resemble crab meat, but usually does not contain real crab meat. Exposure to crab allergens can also occur in occupational settings, such as dust and sewage from seafood factories.

Most of the characterized shellfish allergens are found in the edible body parts (muscle areas) of various shellfish species. The main allergen in shellfish, tropomyosin, is present in the claws and tail of crabs, and arginine kinase is found in the leg muscles of the crab.

Crab is a strong allergen, sometimes causing dramatic manifestations. It can also be considered an occupational allergen for food workers. Shellfish allergy is one of the most common food allergies and usually persists throughout a patient’s life. Most people (about 60%) with shellfish allergies experience their first allergic reaction in adulthood.

Symptoms can be severe and potentially life-threatening, including anaphylaxis. Even a very small amount of shellfish can provoke a reaction. Ingestion of crab in sensitized individuals may result in skin reactions including urticaria, angioedema, eczema, gastrointestinal symptoms (diarrhea, vomiting), systemic reactions (anaphylactic shock), and respiratory symptoms.

Exposure to steam while cooking shellfish has been reported to cause an allergic reaction in some cases due to the presence of allergenic proteins in the steam. Fishermen, processors, shellfish grinders, cooks and even restaurant workers are at risk of developing allergic reactions to shellfish. Smoking may increase the risk of developing snow crab occupational asthma, while atopy may increase the risk of developing occupational snow crab allergy.

Children with seafood allergy have increased levels of specific IgE antibodies with a greater diversity of epitopes than adults. Generally, there are two types of epitopes in food allergens: sequential and conformational. Sensitization to consecutive epitopes is associated with persistent allergy, and the patient may recognize more consecutive IgE epitopes. It has been found that in elderly patients with persistent food allergies, sensitization to specific sequential IgE epitopes is different from that of children, who may outgrow their allergies.

Common major allergens have been identified in crabs, crayfish, shrimp and lobsters. Tropomyosin is cross-reactive among various species of the mollusk family (especially crustaceans) such as shrimp, crabs and lobsters due to identical amino acids (up to 95-100%). In addition, tropomyosin, an invertebrate panallergen, is responsible for cross-reactivity between food and animal aeroallergens.

In invertebrates (crustaceans, molluscs, mites and cockroaches), tropomyosin and arginine kinase are cross-reactive panallergens due to similar phylogenetic identities. Studies have shown that tropomyosin and arginine kinase cross-react with Portunus pelagicus (blue swimming crab) allergens.

Patients allergic to the crustacean family often react to shellfish groups (such as squid or cuttlefish, abalone, snails, oysters, mussels, scallops, clams) as well as mites, cockroaches and parasites.

• Identification of allergens that may cause characteristic symptoms of an allergic disease.
• Suspicion of food allergies in both adults and children.
• Assessing the risk of developing an allergic response to crabs and other seafood.
• Children with food allergies in their parents.
• Doubtful results of skin tests.

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Why does modern medicine need horseshoe crabs? Chemwatch

Virtually unchanged since they first crawled the Earth over 450 million years ago, these ancient creatures (sometimes referred to as living fossils) have outlasted almost every other species – largely due to their incredibly robust immune systems. Their unique way of clotting in the presence of endotoxins makes them incredibly useful in detecting harmful bacteria.

In this article we will take a closer look at horseshoe crabs and what they do for us.

What are horseshoe crabs?

The horseshoe crab is an arthropod species that, despite its name, is technically more closely related to spiders and scorpions than to crabs. There are four species of horseshoe crabs: Atlantic, mangrove, Indo-Pacific and Chinese horseshoe crab.

Limulus polyphemus aka Atlantic horseshoe crab

What makes them so special?

Everything is very simple – their blood. Surprisingly, the mesmerizing blue color – due to the high copper content – is not the most attractive feature of horseshoe crab blood. What scientists are most interested in is the “amoebocytes” it contains. These specialized cells protect horseshoe crabs from bacteria and viruses by gelling and coagulating around these invaders, preventing them from spreading and multiplying in the crab’s system. This immune defense mechanism is not unusual in animals. The uniqueness of the amoebocytes in horseshoe crab blood lies in their extreme sensitivity to lethal endotoxins (cell wall molecules of certain bacteria) and the rapid and violent clotting that occurs once they enter their bloodstream.

When this high sensitivity and rapid blood clotting process was first discovered in 1968, scientists immediately noted the potential for human health applications. Thus began the development of the Limulus Amebocyte Lysate (LAL) test to detect endotoxins produced by harmful bacteria.

The bright blue blood of the horseshoe crab is even more mesmerizing than it looks

Limulus Amebocyte Lysate (LAL) test

The LAL test is named after the creature whose observed immune behavior led to the discovery of this test, the Atlantic horseshoe crab (scientific name Limulus polyphemus ).

LAL’s production process involved collecting horseshoe crabs from the beach and shipping them to one of five production laboratories around the world. There, 30% of the blood is drained from them before returning them to the water. The collected blood is then processed, purified and lyophilized to obtain LAL.

Prior to the introduction of the LAL test, endotoxin testing involved injecting a group of rabbits with a specific sample and closely monitoring their condition for the next four hours. Because the response of rabbits to endotoxins is similar to our human response, a subsequent fever in rabbits would indicate that the test sample was contaminated with endotoxins.

At the time, this method of testing in rabbits was considered a highly effective, albeit very laborious and costly, method for detecting endotoxins. It soon became clear that the LAL test offered a much cheaper, simpler, faster and more effective solution, and the test was adopted as the global standard for screening for bacterial contamination.

LAL testing requires the technician to simply add LAL to the sample and observe the response. Even at concentrations of 1 part per trillion, endotoxins will be detected almost instantly through the formation of a jelly-like clot in the sample.

The LAL test is incredibly important for detecting the presence of endotoxins in pharmaceuticals and medical implants/prostheses. Every product certified (including medical prostheses and implants) by the US Food and Drug Administration (USFDA) must first pass the LAL test. If you have ever received any kind of injection, you should thank the horseshoe crab for its safety!

Future LAL

LAL producers report that the measured mortality rate of 500,000 crabs bled annually is only 15%. However, recent independent studies have shown the number to be closer to 30%-75,000%, corresponding to 150,000-15,000 dead horseshoe crabs annually. Because LAL is so rare and highly prized (one liter can cost up to $1,000!), it’s no wonder manufacturers downplay their mortality rate.

The Atlantic horseshoe crab, currently classified as Vulnerable, is just one level away from Critically Endangered, soon to be followed by Critically Endangered, Extinct in the Wild and Extinct if no action is taken soon. The fate of this species will be in jeopardy if we don’t reevaluate current LAL harvesting practices, and it’s not only humans that will suffer when this species goes extinct. Many coastal birds, fish and turtles that feed on horseshoe crab eggs will also be affected by their extinction.

Critically endangered birds are among the many animals that feast on the protein-rich horseshoe crab eggs.

However, this is not all bad news. In 1995, researchers at the National University of Singapore were able to identify and isolate the gene responsible for the sensitive blood clotting that characterizes LAL. This gene, known as “factor C”, was synthesized in yeast, leading to the creation of “recombinant factor C” (rFC). Synthetic CFL differs from organic CFL in that instead of clotting in response to the presence of endotoxins, synthetic CFL causes the endotoxins to emit fluorescent colors.

Although its discovery was a major breakthrough, regulatory and safety concerns regarding this alternative to LAL have slowed the mass adoption of synthetic LAL. Europe did not recognize rFC as an alternative to LAL until 2015, and the USFDA only approved the first drug tested with rFC in 2018. In 2020, the USP, which sets the scientific standard for drugs in the US, refused to recognize rFC as equivalent to LAL, insisting that its safety has not yet been proven. This is despite the fact that their European, Japanese and Chinese counterparts have recognized and accepted the use of synthetic LALs.

As industry ideals and opinions change slowly, it is likely that the biomedical field will continue to sate their insatiable thirst for the blue blood of these ancient animals for the foreseeable future. This is hardly viable, and we can only hope that we do not reach the point where the choice is made for us through the disappearance of the horseshoe crab.

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