Pubic lice (crabs): symptoms, risk factors and treatment

Pubic lice (crabs): symptoms, risk factors and treatment

Pubic lice (Sing: pubic louse), also known as crab louse, crabs, or Fullers; Latin name Pthirus pubis are tiny parasitic blood-sucking wingless insects that infest the human genitals, causing itching and red spots.

The only other animal known to be affected by this insect is the gorilla. Crabs may also affect other coarse hair on the body, including the eyelashes, eyebrows, beards, mustaches, as well as the hair on the back and abdomen. Pubic lice are about 2mm long and are gray-brown in color.

Pubic lice pass from person-to-person, in most cases as a result of sexual intercourse - close hugging and kissing are also possible routes.

Parents can pass on the lice to their children via the sharing of towels, clothing, bedding or closets (wardrobes); however this is rare. Infested children are at risk of lice spreading to their eyelashes, resulting in possible infections.

Crabs affect sexually active adolescents and adults much more commonly than children. Pubic lice cannot survive for very long away from the warmth and humidity of a human body. Experts say that crabs are the most contagious STD (sexually transmitted disease).

If an infected person has sexual intercourse with a non-infected person, the latter has a 90% risk of getting an infestation, according to The Mayo Clinic.

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Here are some key points about crabs. More detail and supporting information is in the main article.

  • There are approximately 3 million cases of crabs in the US each year.
  • Having pubic lice does not necessarily mean that an individual has poor hygiene.
  • The most common symptom of crabs is itching.
  • Pubic lice can spread to other parts of the body covered in hair, including chests, beards and eyelashes.
  • Crabs are commonly spread through sexual contact.
  • Wearing a condom does not help prevent the spread of pubic lice.
  • Nonsexual transmission of crabs is also possible, through contact with infested materials.
  • Pubic lice can often be diagnosed with the naked eye.
  • Children aged below 18 and pregnant women should discuss treatment with health care providers.
  • Clothes and bedding should be washed in hot water to remove pubic lice.

Symptoms of pubic lice infestation

A symptom is something the patient feels and reports, while a sign is something other people, such as the doctor detect. For example, pain may be a symptom while a rash may be a sign.

Signs and symptoms may not become apparent until one to three weeks after a person comes into contact with the lice. Signs and symptoms may include:

  • Itching in the pubic region - this is not caused by biting from the insect, but from an allergic reaction to the louse saliva and feces (droppings, excrements, stools). The itching is usually worse at night
  • Symptoms of pubic lice include itching, skin lesions and the presence of louse eggs.

  • Red spots and skin lesions - small red bumps or spots may appear. Scratching by the patient may also results in marks
  • Blue spots on the skin - especially on the thighs or lower abdomen
  • Other parts of the body - the lice may spread to the stomach, upper thighs, chest, mustache, and beard. In children they may spread to the eyelashes. Wherever the lice are located, symptoms of itching are common, as well as skin irritation
  • Louse droppings - the presence of dark brown or black powder on the skin or in underwear could indicate the presence of crab droppings
  • Blood in underwear - this is usually caused by scratching by the patient which breaks the skin
  • Adult pubic lice and eggs - an adult pubic louse is smaller than a match head; it is approximately 2mm long. It has six legs and has a gray-brown color. Its back legs are very large, and look like the claws of a crab. The large back legs are used to cling onto the hair.

Eggs are very small, oval shaped, with a yellowish-white color. They stick firmly to the base of the hair.

Both the adult pubic lice and their eggs are visible to the naked eye - some people may need a magnifying glass. You may be able to detect them in coarse hair in the following parts of your body:

  • Along the edge of the scalp
  • In facial hair (beards, mustaches)
  • In the eyebrows
  • In the eyelashes
  • In the hair around the anus
  • In the hair of the armpits
  • In the pubic hair (genital area).

The detection of empty eggshells (nits) after treatment does not mean the infestation is necessarily still present.

Possible complications

If complications to occur they tend to be minor and usually as a result of leaving the infestation untreated.

Skin - intense itching can lead to scratching, which can cause excoriation (skin flakes off) and/or infection.

Eyes - if the eyelashes have been affected there is a risk of:

  • Blepharitis - swelling of the eyelids. The patient will have a foreign body or burning sensation, there may be excessive tearing (liquid tears), itching, photophobia (sensitivity to light), red and swollen eyelids, the whites of the eyes becomes reddened, blurred vision, or crusting of the eyelashes first thing in the morning.
  • Conjunctivitis - there is a thin layer of cells (membrane) between the inner surface of the eyelids and the whites of the eyes, called the conjunctiva. Conjunctivitis is when the conjunctiva becomes inflamed. Another name for conjunctivitis is pink eye. Inflammation causes tiny blood vessels (capillaries) in the conjunctiva to become more prominent, giving the eye a red or pink look.
  • Corneal epithelial keratitis - the cornea becomes inflamed.

On the next page, we look at the causes of pubic lice infestation, how cases are diagnosed and when you should see a doctor about crabs.

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What Are Crabs On The Body? (Video Medical And Professional 2020).

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