Pediculosis: description, symptoms, treatment and prevention

Dermatovenerologist

Khasanova

Alina Rashidovna

9 years experience

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Pediculosis is an infection of the human body by blood-sucking parasites that prefer to settle on the surface of the skin and hair. As a result of the activation of their vital functions and bites, the patient experiences pain, itching and irritation on the skin. Pediculosis occurs more often in children. This may be due to insufficient maturity of the child's immune system, which is unable to resist attacks from parasites. In addition, the disease often results from non-compliance with personal hygiene rules in preschool institutions.

Features of pubic lice

These are small insects - up to 3 mm. Females are noticeably larger than males. They have a flattened oval body that is light brown in color. Three pairs of legs are spread wide, so it seems that the width of the insect is greater than its length. The legs are long and pincer-shaped. The structure allows them to move along triangular hair. They cannot attach to the round hairs that grow on the head, so they do not live on the head.

Like other types of lice, pubic lice go through several stages of development:

• nits – white eggs, inside of which larvae develop; this stage takes up to a week;
• nymphs of stages 1, 2 and 3 – in 15–17 days the parasite goes through three moults and becomes sexually mature;
• adults.

Read more in the article “Incubation period of lice and nits”

Pubic louse lives up to 30 days. During its life it lays about 50 eggs.

Without food, the parasite lives for a day. If unfavorable conditions occur, the pubic louse can fall into a state of suspended animation and spend several months in it. Pubic lice can survive up to two days in water. They can withstand loads of up to 1 kg. For example, on the beach, in the sand, they can exist for several days.

What does a pubic louse look like?

Let's take a closer look at what a pubic louse looks like, and what its bites look like. In the 20s of the last century, Russian scientists E. Pavlovsky and A. Stein described in detail the life cycle of the plant.

In English, the pubic louse is called a crab, due to its external resemblance to a crab. The adult is about 1.3-2 mm long (slightly smaller than body and head lice). It can also be distinguished from other species by its almost round body. Another distinctive feature of Phthirus pubis is that the back two pairs of legs are much thicker than the front legs and have a large claw to hold it firmly on a thread.

The ploshchitsa can climb up its hair, move across its body over short distances, feeds only on blood, drinks blood 4-5 times a day. It moves best at a temperature of about 25-27*C; at a temperature of -5*C it becomes motionless. It can live outside the human body for about two days.

If you leave clothes for three weeks in a dry, closed place, the lice on them will reliably die, and they also die under water within 48 hours. A temperature of 98*C kills them in 7 minutes, a temperature of 54*C in 35 minutes. And from 2% carbolic acid or 2% Lysol they die in about 10 minutes.

The louse has a sense of smell and can smell the human body at a distance of a couple of centimeters. Pavlovsky and Stein, who studied the behavior of lice, believed that there are people who are immune to lice and resistant to infection with lice pubis. Obviously, well-fed individuals do not bite everyone and are sensitive to repellent odors.

Phthirus pubis reproduces relatively slowly

Individuals are dioecious, females lay few eggs, 3 eggs per day at a time. Nit eggs are shaped like a pear with a domed cap. Nits are glued to the hair with a special wax, a product of the adhesive glands secreted by the adult.

What pubic lice bites look like on the human body macula cerulea

A type of pediculosis in which the pubic louse nests on the eyelashes is more common in children and even infants. Very often this type of pediculosis is mistaken for demodicosis.

Where can you find pubic lice?

As mentioned above, pubic lice live on the hairy parts of the human body, but do not affect all the hair. They are attracted to areas with apocrine glands that secrete a special secretion:

• pubis;
• crotch;
• anus;
• scrotum;
• armpits.

The affected areas are always covered with hair. These parasites do not live on smooth skin. The disease occurs in both men and women. Children can also become infected with it if they have hair on their genitals.

Appearance and life cycle of the parasite

Lice are small ectoparasitic insects with mouthparts adapted for piercing skin and feeding on blood. Some of them carry dangerous vector-borne diseases, such as typhus and relapsing fever. Each type of these insects settles on certain animals. Lice come from dog, cat, elk, chicken and others. The following parasites can be found on the human body:

• head louse (Pediculus humanus capitis);
• body louse (Pediculus humanus corporis);
• pubic louse (Pthirus pubis).

Each of these species has its own localization: the head one lives on the scalp, the clothes one lives in underwear. The plot selects areas with hair, excluding the scalp (pubis, axillary areas, facial hair, eyebrows, eyelashes).

Pubic lice are the smallest of these parasites in humans. Adult females reach up to 1.5-2 mm in size, males are slightly smaller, up to 1.3 mm. Their body is brown in color, the intensity of which varies depending on the volume of blood absorbed and the duration of the meal. Parasites on the human body are located at the very base of the hair and resemble slight thickenings on it. Therefore, even imagining what pubic lice look like, detecting them is incredibly difficult.

The body structure of these insects is adapted to a parasitic lifestyle. The body is flattened, trapezoidal in shape, tapering towards the posterior end. There is no clear division into the chest and abdomen. The three pairs of limbs are of unequal length; it increases from the first to the third. The helical twisted claws on the middle pair help the parasites to stay firmly on the hair. There are no wings. Sense organs are antennae and eyes. Pubic lice have poor vision.

The oral apparatus of the louse consists of an upper jaw, a lower lip, shaped like stylets, with which the louse pierces the skin, and a long proboscis located between them for sucking blood. The fold around the mouth, equipped with hooks, helps the flathead to stay on the host while feeding. After the meal, the stilettos and proboscis are hidden in a special cavity inside the head.

Pubic lice are classified as insects with incomplete metamorphosis, since their life cycle consists of 3 stages:

• egg (nit);
• larva (nymph);
• adult insect (imago).

The lifespan of pubic lice is about 3 weeks. A female moth can leave behind about 50 new individuals. The size of nits is 0.5 mm, under a microscope they resemble grains of rice. The eggs are firmly attached to the hair with a special adhesive mass. The duration of this stage is 5-7 days, then the larva emerges from the egg. It differs from the imago only in size and the absence of external genitalia. The nymph stage takes up to 2 weeks. During this time, the individual experiences molting three times. Mating and the first laying of eggs occurs within 1-3 days after transformation into an adult.

The food for pubic lice at the larval and adult stages is exclusively blood; they feed up to 58 times during the day. This feature leads to the fact that parasites cannot exist for a long time outside the human body. The comfortable temperature for life in the flats is 30-33 degrees.

The minimum values ​​at which pubic lice mature is close to 22 degrees. A drop in environmental temperature to +1 degree preserves all stages of parasites in a viable state, while even a short-term increase to 50 degrees is destructive.

How can you become infected with phthiriasis?

There are several ways the disease can spread. The most susceptible to this are women and men who lead an antisocial lifestyle and promiscuous sex life, as well as those who do not maintain personal hygiene.

But you can also catch pubic lice through:

• clothes of a sick person;
• towels and bed linen;
• public toilets;
• beaches, solariums;
• baths, saunas, swimming pools, etc.

Even with careful hygiene, no one is protected from infection, so it is important to be careful when visiting public places and communicating with potential carriers of parasites.

Causes and complications

Infection with pediculosis is always provoked by close contact - with another person, clothing, bed.
The reasons for the increase in incidence are the increase in population, unsanitary conditions, and frequent contact in public places. There are regular cases of reinfection among children - they often interact, and treatment is not carried out comprehensively and responsibly. At risk are children who exchange hats, scarves, headphones, and combs. Head lice infestation can cause complications, especially when it comes to body lice. The latter are carriers of Volyn fever and other vector-borne diseases, as well as typhus. Head lice are more likely to contract louse-borne relapsing fever, although they also carry typhus.

Symptoms of phthiriasis

Pubic lice can be seen without the use of special equipment. They are small, but move quite quickly. Nits are very small and are attached at the very base of the hairs, so they can be very difficult to notice.

In addition to a visual examination, you can find out about the presence of phthiriasis by the following symptoms:

• constant itching - it occurs due to the fact that when bitten, the parasite injects a substance under the skin that is an active irritant;
• small blue dots at the bite sites are traces of an injected substance that prevents blood clotting;
• Due to unbearable itching, a person scratches the skin, skin damage appears, including dermatitis and eczema.

When affected by phthiriasis, a person becomes restless and irritable.

Sometimes symptoms appear even with a small number of parasites on the body. They may not be seen due to the fact that they are hidden in matted and thick curls of hair. In this case, you should consult a doctor to confirm the diagnosis. The specialist uses the following methods for detecting parasites:

• examination with a Wood's lamp - it allows you to see live nits, which in its fluorescent light look white, and dead ones remain gray;
• examination of the affected areas at multiple magnification using a videodermatoscope;
• Examination of the eyes with a slit lamp to detect nits on the eyelashes.

How dangerous is Phthirus pubis?

Fortunately, these insects are not carriers of dangerous diseases, unlike the body and head varieties. But any bites cannot pass without a trace. The consequences appear as:

• Itching and bite marks;
• A bluish spot at the site of the bite.

Interesting! The appearance of a blue spot is associated with the breakdown of hemoglobin under the influence of saliva. The blue color is characteristic of decay products concentrated at the site of the bite.

• Since the bites are scratched, many papules and pustular inflammations form in their place. And if the case is advanced, then pyoderma occurs.
• If eyelashes and eyebrows are affected, blepharitis and conjunctivitis may develop.

Pubic lice, unlike their relatives head and body lice, have a more crab-like structure.

Why is phthiriasis dangerous?

Skin damaged by scratching is favorable conditions for infections to enter the body. The scratched areas become infected, ulcers and boils appear on them. If left untreated, the infection goes deeper into the lymph system. This can lead to systemic diseases and blood poisoning. Pubic lice, with their saliva, transmit infectious diseases, such as typhoid, from person to person.

Many patients experience allergic reactions. Also, phthiriasis is almost always accompanied by sexually transmitted diseases. It could be chlamydia, gonorrhea, syphilis. Pubic lice, passing from person to person, carry the causative agents of these diseases in their saliva. This is precisely what causes the most danger of infection with lice pubis.

When a person is very seriously affected and there are a large number of lice, they do not have enough space to live in the groin and armpits. In this case, they can live on eyebrows and eyelashes. When these areas are affected, conjunctivitis, blepharitis and other eye diseases develop.

Consequences after the disease

In addition to the fact that these parasites bring great discomfort and inconvenience to a person, there is a risk of developing pustular lesions. Itching leads to scratching of the skin, and infection and pyogenic microbes get into these wounds.

If the affected area is the eyelashes, an inflamed red streak appears on the upper eyelid, and conjunctivitis may also develop. Statistics show that 65% of those infected have scabies, and 35% have concomitant sexually transmitted diseases.

Lice themselves do not cause infectious diseases and do not transmit them, but their parasitic lifestyle and wounds on the skin from scratching are ideal conditions for the spread of infections. If treatment does not occur, eczema, boils, and abscesses often develop. Blepharitis forms on the eyelids and the mucous membranes become inflamed.

Only the correct treatment, which a specialist has selected for the patient, taking into account individual indications, can get rid of parasites and prevent the development of complications.

Ways to combat pubic lice

Getting rid of pubic lice is much easier than getting rid of head or body lice. The most effective way is mechanical. That is, you just need to remove all hair from the affected area so that parasites do not have the opportunity to live on the body. They cannot move on smooth skin. The “fashion” for hair removal in intimate areas over the past few years has significantly reduced the incidence of this disease.

If you are infested with pubic lice, you need to shave or otherwise remove the hair on the infected area. It is better to remove hair from the entire body so as not to leave any opportunity for parasites to survive unfavorable conditions nearby. After hair removal, it is advisable to apply pediculicide to the affected area to destroy nits, which, due to their small size, can be hidden in the skin flakes.

If for some reason it is impossible to use the mechanical method, then you can use folk remedies or special preparations that kill lice and nits.

Symptoms and signs of head lice

Detection of head lice and nits

One of the signs of head lice is the detection of insects and their nits. The head louse has an elongated shape, the body of the parasite is transparent or has a grayish-yellow color, and there is sharp pigmentation on the sides. Head lice live on the scalp, most often the back of the head, temple, beard and mustache in men. Lice and nits are visible to the naked eye. Nits are especially noticeable on wet hair.

Rice. 26. The photo shows a head louse and nits with magnification.

Rice. 27. The photo shows head lice nits with magnification.

Rice. 28. The photo shows lice and nits on the hair.

Head lice bites

When sucking blood, lice inject saliva into the thickness of the skin. The saliva secreted by the bean-shaped glands of parasites has an irritating effect, as a result of which inflammatory foci appear on the skin in the form of dense infiltrates, accompanied by itching, often very severe. The presence of papules and itching are the main signs of head lice. Constant scratching causes the development of dermatitis, and the addition of secondary microflora leads to the development of pyoderma.

Rice. 29. In the photo there are traces of head lice bites on the necks of children.

Rice. 30. The photo shows redness of the skin and thickening (inflammatory infiltrates) resulting from head lice bites. The presence of papules and itching are the main signs of head lice.

Itching with head lice

Itching with head lice is one of the leading symptoms of the disease. This makes it similar to atopic dermatitis, which is more common in childhood. The itching will disappear only when all parasites are removed from the scalp. The itching is constant and without treatment, the disease only gets worse over time.

Rice. 31. Itching is the main symptom of head lice.

Skin damage due to head lice

Constant scratching damages the integrity of the skin. Scratch areas with head lice are often infected with streptococci and staphylococci, which causes impetigo, folliculitis and boils. When the scalp is infected with the fungus Trichophyton schonleinii, a bloody scab develops.

In advanced cases, lice eczema appears on the back of the neck. At the same time, regional lymph nodes enlarge and become painful.

Rice. 32. Honey-yellow crusts in places of scratching, which often appear in the occipital and behind-the-ear areas with head lice, indicate the development of a pustular infection (impetigo). Chronic head lice often causes hair loss (photo on the right).

Head lice tangle

With advanced lice, the hair, covered with serous-purulent discharge, sticks together and becomes tangled. The resulting hairball or tangle (trichome) cannot be combed. Currently, matting is rare.

Rice. 33. The photo shows a tangle with head lice. In the photo on the right there are multiple purulent foci, covered with crusts, located under the tangle.

Rice. 34. Lice are constant companions of unsanitary conditions. The photo shows an advanced form of head lice.

Signs and symptoms of linen (body) lice

Linen lice live and lay eggs in the folds and seam areas of clothing and underwear, on clothing - most often in the area of ​​the belt, collar sleeves and cuffs. Despite their inactivity, insects quickly spread among people upon contact. Lice feed on human blood. Their favorite places are the upper back and shoulders, the lumbar and abdominal areas, as well as the groin and thigh areas. Itching, rash and linear scratches localized throughout the body are the main symptoms of linen lice. Body lice carry typhus pathogens.

Rice. 35. In the photo on the left are body lice during feeding. In the photo on the right, the parasite sucked on blood, causing its belly to swell.

Rice. 36. The photo shows a body louse and its excrement.

Rice. 37. The photo shows body lice bites on the skin of the abdomen, back and lower back.

Linen lice bites

After linen lice bites, swellings (papules) from 2 to 4 mm in diameter appear on the skin. The red dot in the center of the papules is the hole from which the insect sucked blood. Along with saliva, an anesthetic substance is injected into the skin during a bite, as a result of which the person notices only a slight tingling sensation.

Some people develop a local allergic reaction to insect bites, resulting in redness of the skin around the papule. Bites usually heal in 3 to 4 days.

Rice. 38. The photo shows body lice bites. The photo on the right shows bites with an allergic reaction.

Itching from lice bites

Itching with linen lice is one of the main symptoms of the disease. Itching leads to damage to the skin (scratches, scratching).

Rice. 39. The photo shows linen lice bites on the skin of the thigh.

Skin damage due to body lice

Scratching with body lice has a linear shape. Over time, the damaged areas become infected and pustular diseases (pyoderma) develop.

With body lice, bluish spots (melasma) often appear on the skin, which are associated with the breakdown of hemoglobin in areas of hemorrhage.

In the chronic course of body lice, the skin becomes dry and thickened, brown pigmentation and fine pityriasis-like peeling appear.

Rice. 40. The skin of the abdomen is one of the favorite feeding places for linen lice.

Rice. 41. With body lice, bluish spots (melasma) often appear on the skin, which are associated with the breakdown of hemoglobin in areas of hemorrhage.

Traces on linen

In the folds and seam areas of clothing and underwear (usually the belt area, collar sleeves and cuffs) you can see a cluster of lice.

Rice. 42. Linen lice in the folds of fabric.

Rice. 43. Linen lice on clothing and synthetic insulation.

Folk remedies

These are the same products that are used to kill hair or body lice and nits. The affected areas are lubricated with the following means:

• vinegar solution;
• pulp of crushed cranberries;
• Castor oil;
• geranium oil

All these options are quite gentle. They do not cause harm to health, but require long-term use for the effect to occur. If they are severely infested with pubic lice, they are powerless. In addition, you will have to leave the product on the affected areas for some time to work. This is not always convenient or appropriate.

More aggressive options can be used:

• 3% hydrogen peroxide;
• boric or sulfur ointments;
• kerosene.

They must be used with great caution, as these products may be toxic or cause burns to the mucous membranes. In addition, they may not be effective against nits.

Body lice

This species does not live on the human body. It lives and hides in the folds of clothing and bedding, which is why the fight against this type of lice is especially difficult and long.

This type of lice has a translucent body measuring 3–5 mm; they are dirty white in color and darken when saturated with blood. In terms of lifestyle, they are more reminiscent of bed bugs, since most of the time they hide in clothes or bedding and can make their way into the thickness of mattresses, pillows, and blankets. This is where the eggs are laid. They do not live directly on human skin or hair, but go there only to feed. Bites most often appear on the upper body - neck, shoulders, back and lower back.

A body louse - or as it is also called, a linen louse - lives for about 35 days, the female can live up to 45 days. During her life cycle, the female lays about 300 eggs. Development to adulthood takes no more than a week.

Infection with body lice occurs much less frequently than with head lice. It is often associated with an antisocial lifestyle, poor hygiene and a rare change of clothes and bed linen.

You can become infected with body lice:

• when trying on clothes;
• when wearing clothes of a sick person;
• when sleeping in a bed infested with lice;
• in crowded places with close contact with the carrier.

Linen lice also cause lice, just like head lice. This is expressed by bites, and they are not in the form of punctures of the skin, but lice can cut off micro-pieces of skin with their jaws. These bites take 4 or more days to heal. At the same time, they itch very much. The parasites' saliva causes hives. It contains a secretion that prevents blood clotting. With severe damage, body temperature rises.

Since linen lice can move from one person to another, they can also carry pathogens of dangerous diseases, such as typhus, etc.

Professional products

Phthiriasis should be treated with medication using effective agents that work against lice and nits. These are pediculicides that kill parasites. You can use drugs based on different active ingredients: Medilis-Permifen, Medilis-Bio, Medilis-Malathion or Medilis-Super. They are available in the form of a spray or emulsions. Each drug is accompanied by instructions for use, which must be strictly followed. Most drugs can be used by people who do not have individual intolerance. Some can be used to treat children from 5 years of age. The result will come within a few minutes or hours.

What other types of lice are there?

As mentioned above, each type of lice lives only on “its” victim. In addition to human lice, people have to deal with pests on their pets. Lice eaters live on dogs and cats. Their difference from human lice is that lice eaters do not feed on blood, but on dead skin flakes and animal hair. In terms of symptoms, lice-eater infestation is similar to human lice. It is also expressed by severe itching. Lice eaters do not spread from pets to humans.

Lice don't just live on cats and dogs. They can live on mice and rats, sheep, horses, pigs and other animals. All types of lice have the same structure. Vary in size. The largest are pork hematopins, whose length reaches 5 mm. And the smallest are hoplopleurae, which infect hamsters whose size does not exceed 1 mm. Also, species can differ in color, although they are all brown-gray, and when saturated with blood they darken to black.

All types of lice have the same nits - capsules in which the larvae develop. They are round and translucent, attached with an adhesive substance to the base of the hairs.

What must be done when treating phthiriasis

Pubic lice can hide not only on a person’s body, but also in his personal belongings. Therefore, during treatment, it is important to treat underwear, clothing, bedding, and towels. It is better to soak all items that can be washed in a pediculicide solution and wash at high temperature, and after drying, carefully iron or treat with a steam generator. Closets where clothes and linen are stored should be washed with a pediculicide solution. It is advisable to treat mattresses and upholstered furniture with a steam cleaner. Since lice can wait out unfavorable times in a state of suspended animation, it is necessary to do a general cleaning and wash all surfaces with an insecticide solution. This will remove insects from the home that could survive the treatment and then return to the human body.

Diagnostics

Establishing the correct diagnosis is not difficult for specialists. For this purpose the following is used:

• Collection of complaints and medical history, during which it is necessary to clarify possible sources of infection (sexual contact, visiting baths, saunas, using other people’s personal belongings).
• Visual inspection of the skin in the affected areas. Can be done using a magnifying glass or loupe.
• A Wood's lamp is used to diagnose intimate lice. Plates that parasitize the human body fluoresce under its glow.
• Pubic lice can be detected using the modern diagnostic method of videodermatoscopy, in which a multiply enlarged image of the examined area of ​​skin is displayed on a computer screen and studied.
• A general blood test, urine test, blood biochemistry, and serological studies are relevant in the presence of bacterial complications of phthiriasis. They make it possible to identify the presence of an inflammatory or allergic process in the body and determine its degree.

The main criterion for making a diagnosis is the detection of adult individuals and nits of pubic lice on the hair in the genital area.

Patients with phthiriasis should also be tested for syphilis, gonorrhea, chlamydia, trichomoniasis and other STIs, since lice pubis is often transmitted in conjunction with other sexually transmitted diseases.

Prevention

Pubic lice can affect anyone, regardless of their lifestyle. To reduce the likelihood of illness, you should take the following measures:

• carefully observe personal hygiene;
• do not engage in sexual contact with strangers;
• do not use other people's bed linen;
• do not wear other people's clothes and underwear;
• do not use other people's towels.

In public places, you should protect yourself as much as possible from lice. For example, you should not sit on the seats in the sauna or in the changing room of the swimming pool without a personal sheet or bedding.

After visiting a place where infection is possible, you must thoroughly wash, wash and iron your clothes with a hot iron. For prevention purposes, it is worth removing hair in intimate areas.

If you suspect a pubic lice infestation, you should consult a doctor and begin treatment, preventing the insect population from increasing many times over. If you start fighting right away, you can get rid of them quickly and without health consequences.

Treatment of pediculosis

The intensive reproduction process and short period of reaching sexual maturity contribute to the rapid spread of insects throughout the scalp. The simultaneous presence of adults, larvae and nits forces the use of drugs that affect lice regardless of their “age”. The most effective remedies against pediculosis pathogens include:

• the use of topical formulations - shampoos, sprays and lotions for hair treatment;
• combing with a fine-toothed comb to mechanically remove insects and nits;
• the use of means to heal bite sites and prevent their suppuration;
• cutting hair to create an easier-to-maintain hairstyle.

An important measure to combat lice is thorough washing and disinfection of clothing and bedding.

Important: if one of the pupils in a kindergarten group is found to have lice, other parents should be notified to more thoroughly monitor possible infestation. The use of self-prepared shampoos and preparations for the treatment and prevention of head lice is not recommended due to their low effectiveness and possible danger to the child’s health.

Danger and possible consequences of infection

Pediculosis pubis is a dangerous disease and very contagious. If it is not treated on time, serious consequences will arise. Constantly scratching the skin due to severe itching can lead to dermatitis or eczema. In addition, the damaged surface is a favorable environment for the penetration of various infections. The occurrence of boils, ulcers, and abscesses cannot be ruled out. In severe cases, even inflammation of the lymph nodes is possible.

A sick person experiences constant discomfort and is unable to get a good night's sleep due to the bites of the squash. Subsequently, he begins to suffer from headaches, neuroses, and depression. Problems arise with the cardiovascular system and other internal organs. There may be an increase in body temperature and loss of appetite.

Parasite bites provoke allergic reactions in the body . If eyelashes or eyebrows are damaged by insects, blepharitis develops. The occurrence of conjunctivitis cannot be ruled out.

Frequently asked questions (FAQ)

The most popular questions and answers to them:

Expert opinion

Alexandra Valerievna

Doctor-Trichologist

How are lice pubis and scabies related?

Both diseases are caused by parasitic insects and are transmitted both sexually and domestically. The scabies mite spreads quickly, as does the scabies mite. After infection, severe itching occurs in the affected areas.

How are head lice different from pubic lice?

They have completely different paw structures, so the pubic area never extends onto the head. It can only move and be held on hair that has a triangular cross-section. The scalp area contains round hair and is more suitable for head lice.