Pediculosis: Cause, Symptoms — Treatment

Pediculosis: Cause, Symptoms & Treatment


Pediculosis is an ectoparasitic infestation caused by blood-feeding lice of the order Phthiraptera. Although pediculosis can infest any part of the body but term “Pediculosis” is used for head pediculosis.

Causes & Types

Pediculosis can be divided into following types based on their location and type of lice which causes it:

  • Pediculosis capitis : Also known as head lice infestation which is caused by lice Pediculosis capitis. This is the commonest type.
  • Pediculosis corporis : Also known as Pediculosis vestimenti or Vagabond’s disease. It is caused by body louse, Pediculus humanus humanus, also known as Pediculus humanus corporis.
  • Pediculosis pubis : Also known as “crabs”. It is caused by Phthirus pubis which looks like crabs, therefore, called Crab louse.

Lice live by feeding on host blood and cannot survive for long without a host. Body lice are responsible for transmission of louse-borne relapsing fever, louse-borne typhus and viral encephalitis.


Pediculosis capitis is the commonest cause of lice infestation that is transmitted by close contact like sharing the bed, combs, brushes when children are playing, direct head-to-head contact etc. Children and women are are typically affected. Overcrowded communities provide an ideal setting for its transmission and infrequent combing and washing predispose to infestation.

After infestation, there is pruritus of the scalp. Pruritus intensifies after 3-4 weeks of infestation. Each egg or ‘nit’ may hatch one nymph that will grow and develop into the head louse. Lice feed on the blood of host once or often each day by piercing the skin with their tiny needle-like mouthparts. While feeding lice excretes their saliva, which irritates the skin and causes itching. Advanced cases complain of pruritus and boils in the scalp or glands in the neck. Unlike scabies, these lice cannot burrow into the skin. Eggs are always detectable even if lice are not seen. They resemble dandruff but can be differentiated by their firm adherence to hair (dandruff can be flicked of hair). They are seen as smooth surfaced oval structures attached to the hair at an angle of about degrees.

Complications may arise due to persistent scratching, includes excoriated papules, which develop a secondary streptococcal infection. Pustules, crusts, and matting of scalp hair characterize this stage. Enlargement of lymph nodes (lymphadenopathy) in the back of the neck (posterior cervical region) is a common presentation of pediculosis capitis.

hair at the back of head and back of ears are commonly affected by nits because these are areas which are least taken care of during grooming.

Pediculosis corporis also causes heavy itching of the body. Body lice are vectors for transmission of disease already mentioned. It affected individuals who are unable to wash off their clothes frequently. Most of these persons lack a home and hence the name, vagabond’s disease.Intense itching leads to searching of the body by the individual for the lice but they cling to clothes which make them difficult to find. Numerous petechial and erythematous macules, papules with hemorrhagic puncta, some in linear array and excoriation typify this disease. Commonly involved areas are upper back, over the scapula, shoulders,below axilla and waistline.

Pediculosis pubis is a sexually transmitted condition which is caused by pubic lice. They infest human pubic hair but may infest other areas like eyelashes causing pediculosis ciliaris. They affect areas like perineum, genitals, perianal region, thighs, lower abdomen and other hairy parts.


Diagnosis of pediculosis is made by the typical finding of itching and demonstration of lice in head with the help of louse comb. The comb should then be examined for the presence of lice.

Pediculosis corporis can be diagnosed by severe pruritus in the trunk, especially in back that is out of proportion or existing skin lesions. Lice and nits can be demonstrated from the clothes.

A pubic louse can be diagnosed with the demonstration of nits, nymphs and adult lice on pubic hair either by removing it with forceps or by cutting hair and examining under lens or microscope.


Pediculosis capitis treatment has to be given to all family members especially those sharing beds and combs with the patient. A single application of Gamma benzene hexachloride (1%), malathion (0.5%) or permethrin (2%) is very effective. It can be repeated after 10 days for more safety. Nits can be killed by applying kerosene (5%) or removed by combing the hair with a fine-toothed comb following application of vinegar (dilute acetic acid) that loosens them. Shampoo can be used to clean the scalp, antihistamines can be given to relieve itching and topical antibiotics for infection or lymph nodes enlargement.

Pediculosis corporis can be treated by washing clothes in boiling water and pressing with a hot iron. Alternatively, clothing can be powdered with disinfectants like DDT (10%), GBH (1%), pyrethrin or malathion. Improving personal hygiene and regular washing of clothes are crucial for preventing recurrence.

Pediculosis pubis can be treated by applying GBH (1%) or Permethrin (2%) on affected areas. Sexual partner of affected person should also be treated. Shaving hair off affected areas is helpful. Piperonyl butoxide and lindane can also be used.

Pediculosis: Causes, symptoms, diagnosis, and treatment

It seems you have been having an itching problem on your head recently. Now people itch their heads when they are generally short on ideas. Haha, its OK I am just joking. Itching is generally a sign of bugs attack on your head. The condition is known as pediculosis. So what is pediculosis? What are its causes? What are its symptoms? How do doctors diagnose it? Can we treat it? Is there any way to avoid this disease?

In this article I have tried to cover the main points concerned with this disease. However in case of any complications or symptoms, consult a physician immediately. Please read on to know more about the problem.

What is Pediculosis and its Types?

Pediculosis is the condition in which the head and other hairy parts of the body start to itch badly.

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Some important points are:-

  • The causing organisms are larvae adults or eggs of lice.
  • Occurs to all warm blood organisms
  • It is a very common condition in India, with over 10 million cases reported every year.
  • Mostly affects children because of their carelessness with personal hygiene

The lice can attack three different locations in different types of the disease. These types are:-

  • The lice attack only the hair on the head.
  • The infection all over the body
  • Infection in the pubic hair on pelvis.

Different types of lice affect different parts of the body. Some important points about the lice which causes it are:-

  • Body lice:- They infest our clothing rather than our body. So dirty clothes are a favorite site for them to lay eggs instead of the base of the body hair. They can contain harmful diseases like typhus
  • Pubic lice:- It is also called the crab louse. It lives and thrives entirely on human blood and human hair respectively. Though pediculosis is a disease of all warm blooded animals, only humans serve as hosts to the crab lice.
  • Head lice:- This is the most common variant of the lice. It affects the head. While eating, it generates saliva which is an irritant for the skin. It is spread through direct contact with infected hair, and through usage of combs or clothes of infected person. The eggs or nits can also spread from which the lice may emerge later. They cannot penetrate the skin.

Head lice Infection

The scientific name is pediculosis capitis. It affects the hair on the head.

Some of the main points are:-

  • It is very common and not a serious condition.
  • They feed only on human blood and can survive only on human hair
  • Infection is slow at first. However after second bite the symptoms develop very quickly.
  • The adults are about 2 to 3 mm long

Symptoms of Head lice Infection

The main symptoms are:-

  • Severe itching in the head
  • Symptoms are severe mostly 3 to 4 weeks after infection.
  • Bites are mild and cannot be felt usually. However the marks can be seen clearly when the hair is parted or on the neck region.
  • In rare cases, skin can rupture or cause bacterial infection. Inflammation of lymph nodes is also rare.

Causes of Head lice Infection

The most common cause is getting the lice on your head. This occurs mostly through direct contact between your own head and the infected hair on someone else’s head. In more uncommon cases it can occur through sharing bed or clothing of infected person. Cleanliness or hair length does not change risk factor.

Diagnosis of Head lice Infection

The following methods are to be kept in mind :-

  • Find live lice- The most easiest way is to run a comb or use a magnifying glass. But be sure u do not think the dead ones to be active. Louse combs are specially suited for this purpose. More concentration is found near ears and towards neck.
  • Find egg shells in the hair. Empty shells do not indicate anything. active shells give a popping sound when pressed.
  • If any member is infected, all other family members might test positive for the infection.

Treatment of Head lice Infection

There are a lot of ways to treat the problem. Some of them are:-

Mechanical ways

  • shaving off all your hair
  • combing your head with a wet comb occasionally. It is best to use a special comb with fine teeth
  • blowing your hair with dry air from a hair dryer.


  • Dimethicone works best without any side effects in most cases. It does not have any chemical effects and works physically.
  • Ivermectin is also effective but causes irritation to skin in some cases
  • Similarly other medicines have either low effectiveness, or high effectiveness and side effects.

Other than these it is a good habit to wash or dry clean places where our head can be like car seats, beds, clothing and so on.

Body lice Infection

The scientific name is pediculosis vestimenti. Some of the important points are :-

  • They do not lay their eggs on the base of body hair.
  • They prefer the fold of our clothing to breed and prosper

Symptoms of Body Lice Infection

They cause severe itching in various parts of body. They also serve as carriers for diseases like typhoid or trench feber.

Causes of Body Lice Infection

Mainly through spreading by direct contact with infected person for a long time. Less commonly caused by sharing personal effects like clothing, bedsheet, or towel.

Treatment of Body Lice Infection

Improving personal hygiene. Washing clothing materials of affected people with hot water. Pediculicide in rare cases to kill the lice on body, in case the problem persists long enough.

Pubic Lice

The scientific name is Pediculosis pubis. The important points related are :-

  • Mainly infects hair in pelvis.
  • Also exists in other areas with hair, like eye lashes
  • Causes severe itching in pubic area

Symptoms of Pubic Lice

Severe itching in the pubic hair. The itching becomes stronger with passing time. Slight discoloration in the affected areas. Careful observation exposes eggs, nits and lice on skin.

Causes of Pubic Lice

The most common cause is sexual activity with infected person. Hence it is more common in adults than children.

Diagnosis of Pubic Lice

It is done through careful examination of pubic hair using a magnifying glass or by cutting a sample hair. Pubic lice may also be a sign of sexually transmitted diseases.

Treatment of Pubic Lice

OTC meds like lice kill lotions help on killing crab lice. Other medicines may be effective but mostly has side effects on most patients. Proper laundering of clothes and beddings and avoiding sexual activity before symptoms disappear. Shaving pubic hair.


Thus we see that pediculosis is just an irritating condition which itself is not much harmful, but can indicate the presence of other diseases that may have been also transmitted. So it is best to avoid this problem just by following some simple rules of personal hygiene.

I hope this article has thrown some light on the matter. Please do not forget to tell me about your thoughts in the comment section.

Head Lice in Children

Medically reviewed by Last updated on Feb 3, 2020.


What do I need to know about head lice?

Head lice are tiny bugs that attach to your child’s hair. They live on tiny amounts of blood from your child’s scalp. They are about the size of a sesame seed. They lay eggs (nits) and attach the eggs to your child’s hair. Anyone can get head lice but it is most common in children ages 3 to 11. Head lice are spread through direct contact. For example, sharing combs, hats, hair ribbons, or hairbrushes can spread lice. Your child may also get lice if he shares pillows, towels, clothes, or blankets.

What are the signs and symptoms of head lice?

Your child will not feel the bites. Your child may have any of the following:

  • Severe itching on the scalp, neck, or ears
  • Nits (tiny ovals that are grey, yellow, or white)
  • Tan or reddish-brown bugs in your child’s hair
  • Small red bumps or a rash on your child’s scalp
  • Swollen lymph glads in your child’s neck
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How are head lice diagnosed?

Your child’s healthcare provider will examine your child’s scalp and hair. He may use a fine-tooth comb to collect the lice and examine them with a microscope.

How are head lice treated?

Lice medicine is used to kill head lice and is available without a doctor’s order. Lice medicine usually come as a shampoo. Use it as directed. If your child has hair past her shoulders, you may need a second bottle of lice medicine. If you are pregnant or breastfeeding, ask your healthcare provider before you apply lice medicine to your child. You may need to reapply in 7 to 10 days if you see more lice. Ask your child’s healthcare provider about using lice medicines if your child is 2 years old or younger. Throw away all lice medicine that you do not use. Keep it away from your eyes. Other medicines may also be given to decrease itching and inflammation.

How can I manage my child’s head lice?

  • Comb your child’s wet hair with a fine-tooth comb. Do this every 3 or 4 days for 2 weeks to remove all lice as they hatch. Wet combing may be the only treatment recommended for children younger than 2 years. To help remove eggs, soak your child’s hair in equal parts water and white vinegar. Then wrap a towel around your child’s head for 15 minutes. Remove the towel and comb his hair with a fine-tooth comb.
  • Remind your child to not scratch his scalp. This can make his symptoms worse. Trim his fingernails or have him wear soft gloves or mittens if scratching is a problem.
  • Do not shave your child’s hair. Do not use pet products, acetone, bleach, kerosene or other flammable products to kill lice.

How can I prevent the spread of head lice?

  • Check family members for lice. Treat those who have lice at the same time. Do not share personal items or bedding.
  • Wash all clothes, stuffed animals, towels, and bedding in hot, soapy water. Dry them on the hot cycle for at least 20 minutes. Items that cannot be washed or dry cleaned should be sealed in an airtight plastic bag for 2 weeks. Vacuum furniture, rugs, carpets, car seats, or other fabrics.
  • Disinfect personal items. Soak combs and brushes in rubbing alcohol for 1 hour. Wash lice combs and clothing your child wore during each lice treatment and after each combing.
  • Tell your child’s school or daycare center. Children that may have been exposed to lice need to be screened and treated. Your child can return to school after he has used lice medicine.

When should I seek immediate care?

  • Your child becomes more irritable or fussy than normal.
  • Your child is dizzy, has nausea or vomiting, or a seizure after using lice medicine.

When should I contact my child’s healthcare provider?

  • Your child has a fever.
  • You still see lice after 2 days of treatment.
  • Your child’s bites become filled with pus or are crusty.
  • Your child’s scalp burns, stings, or is numb after using the lice medicine.
  • You have questions or concerns about your child’s condition or care.

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Pediculosis capitis (Head lice)

Definition of Pediculosis capitis (Head lice)

Head lice are tiny insects that feed on blood from the human scalp. An infestation of head lice, called pediculosis capitis, most often affects children and usually results from the direct transfer of lice from the hair of one person to the hair of another.

A head lice infestation isn’t a sign of poor personal hygiene or an unclean living environment. Head lice don’t carry bacterial or viral infectious diseases.

Over-the-counter and prescription medications are available to treat head lice. Following treatment instructions carefully is important for ridding your scalp and hair of lice and their eggs.

A number of home or natural remedies are used to treat head lice infestations, but there is little to no clinical evidence of their effectiveness.

Symptoms of Pediculosis capitis (Head lice)

You may not be aware of a lice infestation. However, common signs and symptoms can include:

  • Itching. Itching on the scalp, neck and ears is the most common symptom. This is an allergic reaction to louse saliva. When a person has an infestation for the first time, itching may not occur for two to six weeks after infestation.
  • Lice on scalp. Lice may be visible but are difficult to spot because they’re small, avoid light and move quickly.
  • Lice eggs (nits) on hair shafts. Nits stick to hair shafts. Incubating nits may be difficult to see because they’re very tiny and camouflaged to match hair color. They’re easiest to spot around the ears and the hairline of the neck. Empty nits may be easier to spot because they’re lighter in color and further from the scalp. However, the presence of nits doesn’t necessarily indicate an active infestation.

When to see a doctor

See your doctor before you begin treatment if you suspect that you or your child has a head lice infestation. Studies show that many children have been treated for head lice with over-the-counter medications or home remedies when they don’t have an active head lice infestation.

Things often mistaken for nits include:

  • Dead or empty nits from a previous head lice infestation
  • Dandruff
  • Residue from hair products
  • Bead of dead hair tissue on a hair shaft (hair cast)
  • Scab tissue, dirt or other debris
  • Other small insects found in the hair


A head louse is a tan or greyish insect about the size of a strawberry seed. It feeds on human blood that it extracts from the scalp. The female louse produces a sticky substance that adheres each egg to a hair shaft. An egg is attached approximately 3/16 inch (4 millimeters) from the base of the shaft — an environment that provides an ideal temperature for incubating the egg.

The louse life cycle

A louse egg hatches after eight or nine days. What emerges is an immature form of the louse called a nymph. The nymph becomes a mature adult louse after nine to 12 days, and an adult lives for three to four weeks.


Head lice crawl, but they cannot jump or fly. Most often transmission of a head louse from one person to another is by direct contact. Therefore, transmission is most often within a family or among children who have close contact at school or play.

There’s some evidence that brushing dry hair with static electricity may make a louse airborne for a short distance.

Indirect transmission is not likely, but lice may spread from one person to another by items such as:

  • Hats and scarves
  • Brushes and combs
  • Hair accessories
  • Headphones
  • Pillows
  • Upholstery
  • Towels

Indirect transfer also could occur among items of clothing stored together. For example, hats or scarves hung on the same hook or stored in the same school locker could serve as vehicles for transmitting lice.

Risk factors

Because head lice are spread primarily by head-to-head contact, the risk of transmission is greatest among younger people who play or go to school together. In the United States, cases of head lice most often occur in children in preschool through middle school.

Complications of Pediculosis capitis (Head lice)

If your child scratches an itchy scalp from a head lice infestation, it is possible for the skin to break and develop an infection.


Preparing for your appointment

See your family doctor or pediatrician if you suspect your child has head lice. The best practice for determining if a child has an active head lice infestation is the identification of a live nymph or adult louse. Your doctor can carefully inspect your child’s hair and, if necessary, examine suspect items under a microscope before confirming a diagnosis of head lice infestation.

Tests and diagnosis

According to the American Academy of Pediatrics guidelines, the gold standard for diagnosing an active head lice infestation is the identification of a live nymph or adult louse.

These guidelines recommend an examination of wet-hair lubricated with such products as a standard hair conditioner. Your doctor will carefully comb your child’s hair with a fine-toothed comb (nit comb) from the scalp to the end of the hair. If no live louse is found, he or she will likely repeat the entire exam a second time.

Identifying nits

Your doctor will also look for nits in your child’s hair. To find nits, he or she may use a specialized light called a Wood’s light, which causes nits to appear bluish. But the identification of nits does not necessarily confirm the diagnosis of an active infestation.

A live nit needs to be near the scalp to incubate. Nits found more than about 1/4 inch (6 mm) from the scalp are likely dead or empty. Suspect nits can be examined under a microscope to determine if they’re living — evidence of a likely active infestation.

If no live nits are found, they’re probably left from a previous infestation and not evidence of an active infestation.

Treatments and drugs

Your doctor will likely recommend an over-the-counter (OTC) medication that kills lice and some of the eggs. These medications may not kill recently laid eggs. Therefore, an appropriately timed second treatment is usually necessary to kill nymphs after they hatch but before they become adult lice.

Some studies suggest that the ninth day after the first treatment is the ideal time for a second treatment, but other retreatment schedules exist. Ask your doctor for written instructions for a recommended treatment schedule.

OTC products

OTC medications are based on pyrethrin, a chemical compound extracted from the chrysanthemum flower that is toxic to lice. Wash your child’s hair with shampoo with no conditioner before using one of these treatments. Rinsing the hair with white vinegar before washing may help dissolve the glue that holds the nits to the hair shafts. Follow directions on the package for how long to leave the medication in the hair, and rinse your child’s hair over a sink with warm water.

OTC medications include the following:

  • Permethrin (Nix). Permethrin is a synthetic version of pyrethrin. Side effects may include redness and itching of scalp.
  • Pyrethrin with additives (Rid, A-200 Lice Killing). In this OTC medication, pyrethrin is combined with another chemical that enhances its toxicity. Side effects may include itching and redness of the scalp. Pyrethrin shouldn’t be used if your child is allergic to chrysanthemum or ragweed.

Prescription medications

In some geographic regions, lice have developed resistance to OTC medications. Also, OTC treatment may fail because of incorrect use, such as not repeating the treatment at an appropriate time.

If the correct use of an OTC treatment has failed, your doctor may recommend a prescription treatment. These include:

  • Benzyl alcohol (Ulesfia). This product is not toxic to lice but kills them by depriving them of oxygen. Side effects may include redness and itching of the scalp. The use of benzyl alcohol to disinfect medical devices has been shown to cause seizures and other severe reactions in newborn infants. Therefore, lice treatment with benzyl alcohol is not approved for use in children less than 6 months of age.
  • Malathion (Ovide). Malathion is approved for use with people age 6 or older. The medicated shampoo is applied, left to dry naturally and rinsed out after eight to 12 hours. The drug has a high alcohol content, so it can’t be used with a hair dryer or near an open flame.
  • Lindane. This medicated shampoo has a risk of severe side effects, including seizures, and is used only when other treatments have failed. It is not recommended by the American Academy of Pediatrics for use on children. The Food and Drug Administration (FDA) warns that it should not be used on anyone who weighs less than 110 pounds (50 kilograms), is pregnant or breast-feeding, has a history of seizures, or has HIV infection.

Lifestyle and home remedies

If you prefer not to use a medication for treating a head lice infestation, you may consider an alternative home treatment. There is little to no clinical evidence of the effectiveness of such treatments.


Combing wet hair with a fine-toothed nit comb may remove lice and some nits. Research is inconclusive on the effectiveness of this method.

The hair should be wet, and you should add something to lubricate the hair, such as a hair conditioner. Comb the entire head from scalp to end of the hair at least twice during a session. The process should be repeated every three to four days for several weeks — at least two weeks after no more lice are found.

Essential oils

Small clinical studies have suggested that some natural plant oils may have a toxic effect on lice and eggs. These products include:

  • Tea tree oil
  • Anise oil
  • Ylang ylang oil
  • Nerolidol, a chemical compound found in many plant oils

These products are not required to meet safety, efficacy and manufacturing standards used for drugs approved by the FDA.

Smothering agents

A number of household products are used to treat head lice infestations. The reasoning is that these products deprive the lice and incubating eggs of air. The product is applied to the hair, covered with a shower cap and left on overnight. Products used for this purpose include:

  • Mayonnaise
  • Olive oil
  • Butter
  • Petroleum jelly

Dangerous products to avoid

Flammable products, such as kerosene or gasoline, should never be used to kill lice or to remove nits.

Household cleaning

Lice usually don’t live past one day without feeding from a scalp, and eggs do not survive if they aren’t incubated at the temperature near the scalp. Therefore, the chance of lice surviving on household items is small.

As a precaution you may clean items that the affected person has used in the last two days. Cleaning recommendations include the following:

  • Wash items in hot water. Wash bedding, stuffed animals and clothing in hot, soapy water — at least 130 F (54.4 C) — and dry at high heat.
  • Clean hair care items. Clean combs, brushes and hair accessories in hot, soapy water.
  • Seal items in plastic bags. Seal items that cannot be washed in plastic bags for two weeks.
  • Vacuum. Give the floor and upholstered furniture a good vacuuming.


It’s difficult to prevent the spread of head lice among children in child care facilities and schools because there is so much close contact. And the chance of indirect transmission from personal items is slight.

However, it is generally a good practice for children to hang their garments on a separate hook from other children’s garments and not to share combs, brushes, hats and scarves. A worry about head lice transmission is not considered a good reason to avoid sharing protective headgear for sports and bicycling when sharing is necessary.

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