LICE

INTRODUCTION

• LICE are tiny insects that live on humans and feed on blood.
• When a large number of lice live and multiply on a person, it is called an infestation.

Three different kinds of lice live on humans:

Head lice 

• Are usually found in hair, most often on the back of the neck and behind the ears.
• Head lice are common in preschool and elementary school-age children.
• Adults can get them too, especially adults who live with children.

Pubic lice 

• Also called crabs, are usually found in the pubic area.
• But they may also be found on facial hair, on eyelashes, on eyebrows, in the armpits, on chest hair, and, rarely, on the scalp.

Body lice 

• live and lay eggs (nits) in the seams of clothing. 
• The lice are on the body only when they feed.
• Lice spread easily from one person to another through close contact or through shared clothing or personal items (such as hats or hairbrushes). A louse cannot jump or fly.

The most common symptom of lice is itching.

There are different symptoms, depending on which type of lice you have.

Head lice 

-may not cause any symptoms at first.

-Itching on the scalp may start weeks or even months after lice have started to spread.

-Scratching can make the skin raw.

-The raw skin may ooze clear fluid or crust over, and it may get infected.

Pubic lice cause severe itching.

-Their bites may cause small marks that look like bruises on the torso, thighs, or upper arms.

-If pubic lice get on the eyelashes, the edges of the eyelids may be crusted.

-You may see lice and their eggs at the base of the eyelashes.

Body lice 

-cause very bad itching, especially at night.

-Itchy sores appear in the armpits and on the waist, torso, and other areas where the seams of clothes press against the skin. The lice and eggs may be found in the seams of the person's clothing but are typically not seen on the skin.

Frequent scratching can cause a skin infection. 

In the most severe cases of head lice, hair may fall out, and the skin may get darker in the areas infested with lice.

CLASSIFICATION

• Anoplura: sucking lice, occurring on mammals exclusively
• Rhynchophthirina: parasites of elephants and warthogs
• Ischnocera: mostly avian chewing lice, however, one family parasitizes mammals
• Amblycera: a primitive suborder of chewing lice, widespread on birds, however, also live on South-American and Australian mammals

It has been suggested that the order is contained by the Troctomorpha suborder of Psocoptera.

CAUSES

Lice are very easily spread, usually through close personal contact.

Lice infestation may be caused by any of the three types of lice:

Head lice 

• May be spread through close personal contact, shared personal items (combs, brushes, hats, helmets, clothing, or earphones), or shared bedding.

Pubic lice 

• Are spread mainly through sexual contact and are very contagious.
• Most people become infected after a single exposure to an infected person.
• The lice and eggs may also survive long enough on personal items such as clothing or towels to be spread to another person.
• A child who has pubic lice may have a history of sexual abuse.

Body lice 

• Are most often spread by contact with personal items, especially clothing and hats.
• They are sometimes spread by direct personal contact.
• Lice are spread from human to human.
• Pets don't get head lice and can't spread them to humans.

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 start 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 before.
• 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 camera.gif 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 marks (maculae cerulea) that look like bruises 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. 

-Pubic lice tends to be spread by sexual contact.

-If you or your teen has pubic lice, you may also have some other sexually transmitted infection (STI).

-Symptoms of STIs can include itching, tingling, burning, or pain of the genitals. For more information about STIs, see the topic Sexually Transmitted Infections.

TREATMENT

1. Lice will not go away without proper treatment.
2. Treatment should begin as soon as symptoms of lice are noticed or when live lice and eggs (nits) are seen on the person's body or in clothing.
3. Specific treatment depends on the type of lice infestation.

Head lice and pubic lice :

• Killed with over-the-counter or prescription medicines applied to the skin or scalp, and sometimes with a prescription pill.
• The most common way to treat lice is to use medicated creams, lotions, or shampoos that kill lice.
• Some people use a comb to remove head lice and their eggs in addition to or instead of using medicine. 
• In Britain, where lice have become resistant to medicated lotions and shampoos, one study found that using fine-toothed combs with a conditioner (wet-combing) helped get rid of head lice.

Body lice, which live and lay eggs in the seams of clothing, are destroyed by 

• Washing clothing in hot water [130 °F (54.4 °C) or higher] for 5 minutes or more.
• This will usually kill adult lice and prevent eggs from hatching.
• Body lice are only present on the skin when they feed and will usually go away if you bathe daily and wear clean clothes.

Children with head lice can return to school or day care after their first treatment.
Some schools have a "no nits" policy in which the child can go back to school or day care only after eggs have been removed.

 "No nits" policies are discouraged by medical experts. Most doctors agree that a child should be allowed to return to class after proper treatment and should be urged to avoid close head-to-head contact with other students.

Confidentiality should be maintained so as not to embarrass a child who has head lice.

Itching may continue even after all lice are destroyed.

This happens because of a lingering allergic reaction to their bites.

Over-the-counter cortisone (corticosteroid) creams or calamine lotion may help. 

For severe itching, antihistamine medicines (such as Benadryl) or stronger, prescription-strength corticosteroid creams may be needed.

Don't give antihistamines to your child unless you've checked with the doctor first. And don't use cortisone cream for longer than 7 days without talking with your doctor.

Do not use the cream on children younger than age 2 unless your doctor tells you to. 

Don't use it in the rectal or vaginal area in children younger than age 12 unless you've checked with the doctor first.

PREVENTION

• Head lice camera.gif are easily spread among children because kids commonly share hats, combs, and other items.
• If you or your child has head lice, you can help prevent others from getting it if you avoid head-to-head (hair-to-hair) contact during activities inside the home and outside the home.
• Don't share clothing, bedding, hair brushes and accessories, pillows, stuffed animals, or towels.
• Frequently examining the scalps of your school-age children may help you discover and treat lice before they spread to the rest of your family.
• Avoiding prolonged close contact with a person who has lice will also reduce your risk.

• Pubic lice camera.gif are spread primarily among people who have many sex partners.
• Reducing the number of sex partners you have may help reduce your risk of getting pubic lice.

• Body lice camera.gif may be prevented by bathing regularly and changing clothes daily.
• Body lice live on clothing, not on the body. Washing clothing in hot water [130 °F (54.44 °C) or higher] will usually kill adult lice and prevent eggs from hatching.
• Body lice that are on the skin usually go away on their own with daily bathing and wearing clothes that are not contaminated.
• Medicines to kill body lice are usually not needed.
• To help control the spread of lice, you can also clean combs, brushes, clothing, and other personal items to kill lice and their eggs.

OTHER TREATMENT

• Some people try other treatments (such as using petroleum jelly or olive oil to smother lice).
• But there is not strong evidence that other treatments such as these work well or are safe to treat lice.
• Head-shaving helps get rid of head lice.
• But this method can cause distress to the person whose head is shaved. 
• After cutting or shaving the hair, put the hair into a garbage bag right away and seal it so that lice cannot spread to other areas in your home.

REFERENCES : LICE