Pubic Lice
Pubic lice,
Pthirus pubis (also
called “crabs” because of their resemblance ) are
one of three kinds of human lice in the large group of lice
families, the others being Pediculus
humanus capitis
(head louse) and Pediculus humanus corporis (body louse).
Pubic lice are small, six-legged,
wingless, grey parasites about 1 to 3 mm long. They can live in
almost any type of human hair, but is found mainly in the pubic
hair. Lice have claws on their legs that are adapted for feeding and
clinging to hair or clothing. Their body shape is oval and broader
than long, with four distinct lobe-like protuberances on each side
of their abdomen.
The pubic or crab
louse is quite distinct in appearance; it has pincerlike claws
resembling those of sea crabs. Lice are blood-sucking insects. They
feed on human blood several times daily. They stay close to the skin
for moisture, food, and warmth. They move freely and quickly, which
explains their ease of transmission. A fertilized female louse lays
about 10 eggs a day for up to a month until it dies. Pubic lice may
be found on the short hairs of the body, areolar hair, axillary
hair, beard, scalp margins, eyebrows, and eyelashes, in addition to
pubic hair.
Lice infestation (pediculosis) is a
common sexually-transmitted condition and is found mostly in
adolescents. It is usually transmitted through sexual contact, but
it can also be transmitted through physical contact with
contaminated objects such as toilet seats, sheets, and blankets.
Some women have acquired it while trying on swimming suits at a
store. The individual louse can survive for about 24 hours apart
from its necessary human host.
In the United States
pediculosis affects 6-12 million
people annually. Pediculosis has a worldwide distribution and is
endemic both in developing and developed countries. Also it is more
common in women than in men and it can affect any age group.
SIGNS AND SYMPTOMS
When the infestation consists of many
adult lice the symptoms are felt immediately, but when it consists
of a few lice, that then lay eggs, symptoms appear only after the
eggs have hatched, which may last between two to four weeks.
The typical symptom of pediculosis is
itching. Because it needs blood to survive, the louse buries its
head inside a pubic hair follicle. It excretes a substance into the
skin that causes the itching. Itching becomes worse at night.
Sometimes, the place where the louse
bit, a red papule appears and the area may become inflated.
If the infestation is left
untreated, the infected individual can become sensitised. Continual
scratching may lead to secondary infections and in some cases
swollen lymph glands, due to bacterial infection. If the infestation
involves the eyelashes, and left untreated, the eyelids can become
swollen and inflamed.
TREATMENT
Pubic lice are easily treated with
a 1% Permethrin or
Pyrethrin lice shampoo, but the pubic hair must be shaved or combed
with a fine-toothed comb to remove the nits.
Wet combing or application of diluted vinegar or commercial
preparations of 8% formic acid may help in the removal of nits or at
least make the combing easier. Plastic or the sturdier metal nit
combs may be used.
Because lice can survive apart from
its human host,
linen, clothing, and
other materials must be disinfected.
Temperature exceeding 131°F (55°C) for more than 5 minutes kills
eggs, nymphs, and mature lice.
PREVENTION
In order to prevent a pubic lice
infestation you should avoid having sex with an infected person or
limit the number of your sex partners. Because pubic lice can also
be contracted from bedding and towels used by an infested person it
is important to avoid contact with any item that he/she has used.
Also a good hygiene is very important.
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