pubic lice

Introduction about pubic lice

“Crabs” (the name given to pubic lice) can often be a source of itching (itching) due to their bites. They are easily transmitted between two or more individuals. Pubic lice particularly affect people between the ages of 15 and 35.
They cause lesions that are generally benign. However, repeated treatment with insecticides can lead to problems of toxicity, intolerance, allergy or nit resistance.


The pubic louse ( Phtirius inguinalis ) or “crab” is an insect that preferentially lives in the pubic region. It feeds on human blood, piercing the skin of the parasitized person. At the same time, it releases a substance that can cause the skin to itch or become inflamed. It’s pediculosis or phtyriasis.

Pubic lice measure between 1 to 3 mm (often <2 mm), their size is smaller than head lice and body lice. It has a shape similar to that of crabs. Its lifespan is two weeks. He has two pairs of paws that allow him to cling to fur.

The adult louse can deposit up to 25 eggs (nits) per day at the base of its host’s hair. Their hatchlings hatch in six to eight days after spawning. The louse prefers to shelter in the pubic area, but sometimes, it can be found around the anus, in the armpits, chest, beard and eyebrows.


Sexual transmission  
Pubic lice are transmitted exclusively by inter-human contamination. In fact, man can be infected directly or indirectly. Direct transmission occurs by direct contact between humans, mainly between sexually active individuals. Sexual intercourse with an infected person is very frequent. Therefore, phtyriasis is one of the sexually transmitted diseases. Sexual intercourse is the main route of transmission of pubic lice.

Another route of transmission    
Lice can, more rarely, be transmitted indirectly through contact with contaminated clothing, towels, sheets and other items. Far from its host, which is man, an adult louse dies within 24 hours, whereas nits can resist for eight days. Unlike other lice, good hygiene and the use of a condom do not protect against lice. Close contact with contaminated people or objects is enough for a person to become infected.
Know that pubic lice found in toilet bowls cannot be transmitted to a human being.


Location of symptoms
Symptoms occur mainly at the level of the pubis, and more rarely in the short hairs of the anus, thorax (chest), armpits, beard, eyelashes or eyebrows.

Main symptom:
The early and main sign of phthiriasis is a strong and permanent itch. It is associated with redness and swelling of the skin. The itching tends to intensify during the night.

Duration of symptoms  :
Please note that the itching sensation may last for some time after treatment. However, some people with head lice don’t feel it.

– The act of scratching can cause small wounds that can be complicated and lead to the formation of pus. You can see the “crabs” as small red dots, and the nits as fixed dots near the base of the pubic hair. They are more easily recognizable, as they are often numerous.
– You can also see blue dots on the surface of the skin, these are the marks of the lice bite.
– Some brown or black particles can settle in the bottom of the individual’s pants. These are called the “slip sign”, which correspond to the droppings of the lice.
– Fever may occur depending on the extent of the infection.
– In rare cases, children can suffer from blepharitis, i.e. an inflammation of the eyelid where lice can settle.
– In addition, the existence of manifestations of other sexually transmitted diseases is possible.


Treatment of pubic lice according to European guidelines ( European guideline , see references at end of process) – 2017 Recommendations

First line therapy –
Permethrin 1%. Leave to act for 10 minutes and then rinse, repeat 7 to 10 days later.

– Pyrethrins with piperonyl butoxide (in English: Pyrethrins with piperonyl butoxide ). Leave to act for 10 minutes and then rinse, repeat 7 to 10 days later.

Second line ( Second line therapy )
– Phenothrin 0.2%, let it act for 2 hours and then rinse.
– Malathion 0.5% (eg Prioderm®), leave to act for approx. 12 hours and then rinse.
– Ivermectin to be taken orally at a dose of 250 or 400 μg/kg in a single dose, repeat after 7 days. A single dose of 400 μg/kg is recommended especially in severe cases.

Other therapies  In
some countries, such as the United States, there are topical treatments with 0.5% ivermectin (Sklice lotion, registered in the United States to act against head lice) and 25% lotion of benzyl benzoate. . In 2017, these topical treatments were still under discussion due to their effectiveness. This is one of the reasons why these European recommendations are classified under Other therapies and not first or second line.

Notes on treatments:
– Pregnant or breastfeeding women, children or asthmatics also need special recommendations from health professionals. It is the same in the case of wounds, whether they are infected or not.
– It has been found that pubic lice are less sensitive to insecticides. As a result, practitioners tend to adopt the mechanical method without ill effect. A greasy cream, such as petroleum jelly or dimethicone (also read our full file on lice), having a lice-asphyxiating property when applied for ten days.
– In addition, removing all nits using tweezers or a fine-toothed comb helps to completely eradicate these lice. Shaving is not enough, but reinforces the treatment.

For pediculosis of the eyelashes (palpebral phthiriasis), the following treatments are recommended, as summarized on the website in December 2017:
– ivermectin taken orally in 2 doses of 200 μg/kg, one week apart.
– 1% permethrin (Loxazol®, off-label use), to apply to the eyelashes, leave on for 10 minutes and then rinse.
– ophthalmic ointment based on paraffin or yellow mercury oxide: topical application 2x a day for 8-10 days would be effective in asphyxiating the parasites. Dead lice and nits must be removed manually.

natural treatment

Natural pyrethrins are substances extracted from the chrysanthemum flower. Packaged in a spray lotion with synthetic pyrethroids, they kill lice and nits in a single application. Spray all over the infected area. Then proceed with cleaning with soap. Rinse with water after letting the product act for half an hour. It is advisable to repeat the treatment for eight to ten days.

You can also put coconut oil on the area to be treated. This technique is intended to suffocate parasites. Lavender can also be used to ease the discomfort generated by head lice. Shave the pubic hair first, then apply flower lotion mixed with vinegar.

Advice & Prevention

The first way to “fight” head lice is prevention:

– Avoid intimate relationships with people suspected of having head lice

– Only use your own towels

If you are infected with head lice:

– Avoid scratching to avoid accidental injuries. They become “gateways” for microbes

– Start treatment as soon as possible, because it is the only way to get a more effective cure

– Abstain from sex until healing

– Take tests to detect and treat other venereal diseases (STIs), such as HIV, hepatitis (B and C) and syphilis . This advice also applies to your sexual partner.

– Encourage your partners, who will be examined and treated;

– When repeated treatments fail, beware of the effects of chemicals, and consult a health professional.

– Wash clothes, underwear, towels and sheets at 60°C (or by dry cleaning). It is also possible to place all these tissues in a waterproof plastic bag for about 3 days.

Jeanne Kenney
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I’m a stylist trainer, a content creator, and an entrepreneur passion. Virgo sign and Pisces ascendant, I move easily between my dreams, the crazy world I want, and my feet on the ground to carry out my projects.

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