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Lice - Symptoms
Itching, the most common symptom of all types of lice infestation, is caused by an allergic reaction. Lice bite the skin to feed on a person's blood. The saliva from these bites causes the allergic reaction and itching.
Itching may not occur right away, depending on a person's sensitivity and history of lice infestation. The first time a person is infested with lice, it may take several weeks or months for itching to develop or to be noticed. In a repeat case of lice, a person may begin to itch within 2 days of infestation because the immune system reacts more quickly when exposure has occurred previously.
Some people become very sensitive to lice bites and have unbearable itching. Others build up tolerance to the bites and have little or no itching, even with repeated infestations.
In addition to itching, symptoms of lice infestation vary depending on which type of lice is present.
Head lice
Head lice
and their eggs (nits) can be
seen on hair, the nape of the neck, and behind the ears. They can vary in color
from white to brown to dark gray. The eggs are tiny round or oval shapes that
are tightly attached to the hair near the scalp and do not slide up and down on
the hair.
Frequent scratching may cause broken skin or sores to
form on the scalp. The damaged skin may weep clear fluid or crust over, and it
may become infected. In response to infection, the
lymph nodes behind the ears and in the neck may become tender and
swollen.
Pubic lice
A
pubic lice infestation may cause itching around the genitals as well as the
anus, armpits, eyelashes, and other body areas with hair. Pubic lice bites may
cause small, flat, blue-gray, bruiselike marks (maculae cerulea) on the torso,
thighs, or upper arms. The marks may last for several months, even after all
lice have been killed. Pubic lice, like head lice, can be seen on shafts of
hair.
Pubic lice that infest the eyelashes and eyelids may cause irritation and crusting in those areas. The lice may be visible near the base of eyelashes.
Up to one-third of people who have pubic lice also have some other sexually transmitted disease (STD).1Symptoms of STDs can include itching, tingling, burning, or pain of the genitals. For more information about STDs, see the topic Exposure to Sexually Transmitted Diseases.
Body lice
Itchy sores from
body lice usually develop in the armpits, around the waist, and along the
trunk where seams of clothes press against the skin. The lice and eggs are
generally not seen on the skin but may be found in the seams of the person's
clothing.
Other conditions, such as dandruff or scabies, can cause symptoms similar to those of a lice infestation.
WebMD Medical Reference from Healthwise
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