pediculosis

Head lice are tiny insects that live on people's heads. Adult lice are about the size of sesame seeds. The eggs, called nits, are even smaller - about the size of a dandruff flake. Lice and nits are found on or near the scalp, most often at the neckline and behind the ears.

Head lice are parasites, and they need to feed on human blood to survive. They are one of the three types of lice that live on humans. The other two types are body lice and pubic lice. Each type of lice is different, and getting one type does not mean that you will get another type.

Lice move by crawling, because they cannot hop or fly. They spread by close person-to-person contact. Rarely, they can spread through sharing personal belongings such as hats or hairbrushes. Personal hygiene and cleanliness have nothing to do with getting head lice. You also cannot get pubic lice from animals. Head lice do not spread disease.

Children ages 3-11 and their families get head lice most often. This is because young children often have head-to-head contact while playing together.

The symptoms of head lice include:

• Tickling feeling in the hair
• Frequent itching, which is caused by an allergic reaction to the bites
• Sores from scratching. Sometimes the sores can become infected with bacteria.
• Trouble sleeping, because head lice are most active in the dark

A diagnosis of head lice usually comes from seeing a louse or nit. Because they are very small and move quickly, you may need to use a magnifying lens and a fine-toothed comb to find lice or nits.

Treatments for head lice include both over-the-counter and prescription shampoos, creams, and lotions. If you want to use an over-the-counter treatment and you aren't sure which one to use or how to use one, ask your health care provider or pharmacist. You should also check with your health care provider first if you are pregnant or nursing, or if you want to use a treatment on a young child.

Follow these steps when using a head lice treatment:

• Apply the product according to the instructions. Only apply it to the scalp and the hair attached to the scalp. You should not use it on other body hair.
• Use only one product at a time, unless your health care provider tells you to use two different kinds at once
• Pay attention to what the instructions say about how long you should leave the medicine on the hair and on how you should rinse it out
• After rinsing, use a fine-toothed comb or special "nit comb" to remove dead lice and nits
• After each treatment, check your hair for lice and nits. You should comb your hair to remove nits and lice every 2-3 days. Do this for 2-3 weeks to be sure that all lice and nits are gone.

All household members and other close contacts should be checked and treated if necessary. If an over-the-counter treatment does not work for you, you can ask your health care provider for a prescription product.

There are steps you can take to prevent the spread of lice. If you already have lice, besides treatment, you should:

• Wash your clothes, bedding, and towels with hot water, and dry them using the hot cycle of the dryer
• Soak your combs and brushes in hot water for 5-10 minutes
• Vacuum the floor and furniture, particularly where you sat or lay
• If there are items that you cannot wash, seal them in a plastic bag for two weeks

To prevent your children from spreading lice:

• Teach children to avoid head-to-head contact during play and other activities
• Teach children not to share clothing and other items that they put on their head, such as headphones, hair ties, and helmets
• If your child has lice, be sure to check the policies at school and/or daycare. Your child may not be able to go back until the lice have been completely treated.

There is no clear scientific evidence that lice can be suffocated by home remedies, such as mayonnaise, olive oil, or similar substances. You also should not use kerosene or gasoline; they are dangerous and flammable.

Centers for Disease Control and Prevention

Body lice (also called clothes lice) are tiny insects which live and lay nits (lice eggs) on clothing. They are parasites, and they need to feed on human blood to survive. They usually only move to the skin to feed.

Body lice are one of the three types of lice that live on humans. The other two types are head lice and pubic lice. Each type of lice is different, and getting one type does not mean that you will get another type.

Body lice can spread diseases, such as typhus, trench fever, and relapsing fever.

Body lice move by crawling, because they cannot hop or fly. One way that they spread is through physical contact with a person who has body lice. They can also spread through contact with clothing, beds, bed linens, or towels that were used by a person with body lice. You cannot get lice from animals.

Body lice is most common in people who cannot bathe and wash their clothes regularly, especially if they live in crowded conditions. In the United States, this is most often people experiencing homelessness. In other countries, body lice can also affect refugees and victims of war or natural disasters.

The most common symptom of body lice is intense itching. There may also be a rash, which is caused by an allergic reaction to the bites. The itching causes some people to scratch until they get sores. Sometimes these sores can become infected with bacteria or fungi.

If someone has body lice for a long time, the heavily bitten areas of their skin can become thickened and discolored. This is most common around your midsection (waist, groin, and upper thighs).

A diagnosis of body lice usually comes from finding nits and crawling lice in the seams of clothing. Sometimes a body louse can be seen crawling or feeding on the skin. Other times it takes a magnifying lens to see the lice or nits.

The main treatment for body lice is to improve personal hygiene. That means regular showers and washing clothes, bedding, and towels at least once a week. Use hot water to wash the laundry, and dry it using the hot cycle of the dryer. Some people may also need a lice-killing medicine.

Centers for Disease Control and Prevention

Pubic lice (also called crabs) are tiny insects which usually live in the pubic or genital area of humans. They are also sometimes found on other coarse body hair, such as hair on the legs, armpits, mustache, beard, eyebrows, or eyelashes. Pubic lice on the eyebrows or eyelashes of children or teens may be a sign of sexual exposure or abuse.

Pubic lice are parasites, and they need to feed on human blood to survive. They are one of the three types of lice that live on humans. The other two types are head lice and body lice. Each type of lice is different, and getting one type does not mean that you will get another type.

Pubic lice move by crawling, because they cannot hop or fly. They usually spread through sexual contact. Occasionally, they may spread through physical contact with a person who has pubic lice, or through contact with clothing, beds, bed linens, or towels that were used by a person with pubic lice. You cannot get pubic lice from animals.

Since they spread mainly through sexual contact, pubic lice are most common in adults.

The most common symptom of pubic lice is intense itching in the genital area. You may also see nits (lice eggs) or crawling lice.

A diagnosis of a pubic lice usually comes from seeing a louse or nit. But lice and nits can be difficult to find because there may be only a few present. Also, they often attach themselves to more than one hair, and they do not crawl as quickly as head and body lice. Sometimes it takes a magnifying lens to see the lice or nits.

People who have pubic lice should also be checked for other sexually transmitted infections (STIs), and their sexual partners should also be checked for pubic lice.

The main treatment for pubic lice is a lice-killing lotion. Options include a lotion that contains permethrin or a mousse containing pyrethrins and piperonyl butoxide. These products are available over-the-counter without a prescription. They are safe and effective when you use them according to the instructions. Usually one treatment will get rid of the lice. If not, you may need another treatment after 9-10 days.

There are other lice-killing medicines that are available with a prescription from your health care provider.

You should also wash your clothes, bedding, and towels with hot water, and dry them using the hot cycle of the dryer.

Centers for Disease Control and Prevention

Germs, or microbes, are found everywhere - in the air, soil, and water. There are also germs on your skin and in your body. Many of them are harmless, and some can even be helpful. But some of them can make you sick. Infectious diseases are diseases that are caused by germs.

There are four main types of germs:

• Bacteria are one-celled germs that multiply quickly. They may give off toxins, which are harmful chemicals that can make you sick. Strep throat and urinary tract infections are common bacterial infections.
• Viruses are tiny capsules that contain genetic material. They invade your cells so that they can multiply. This can kill, damage, or change the cells and make you sick. Viral infections include HIV and the common cold.
• Fungi are primitive plant-like organisms such as mushrooms, mold, mildew, and yeasts. Athlete's foot and yeast infections are common fungal infections.
• Parasites are animals or plants that survive by living on or in other living things. Malaria and head lice are infections that are caused by parasites.

There are many different ways that you can get an infectious disease, depending on the type of germ. They can include:

• Through direct contact with a person who is sick. This includes kissing, touching, sneezing, coughing, and sexual contact. Pregnant people can also pass some germs along to their babies.
• Through indirect contact, when you touch something that has germs on it. For example, you could get germs if someone who is sick touched a door handle, and then you touch it.
• Through insect or animal bites.
• Through contaminated food, water, soil, or plants.

Infectious diseases can cause many different symptoms. Some are so mild that you may not even notice any symptoms, while others can be life-threatening.

There are treatments for some infectious diseases, such as antibiotic, antiviral, antifungal and anti-parasitic medicines. But for other infections, such as some caused by viruses, you can only treat your symptoms while you wait for your immune system to fight off the germ.

You can take steps to help prevent many infectious diseases:

• Get vaccinated.
• Wash your hands often.
• Pay attention to food safety.
• Avoid contact with wild animals.
• Use a latex condom every time you have sex. If your or your partner is allergic to latex, you can use polyurethane condoms.
• Don't share items such as toothbrushes, combs, and straws.

Parasites are living things that use other living things - like your body - for food and a place to live. You can get them from contaminated food or water, a bug bite, or sexual contact. Some parasitic diseases are easily treated and some are not.

Parasites range in size from tiny, one-celled organisms called protozoa to worms that can be seen with the naked eye. Some parasitic diseases occur in the United States. Contaminated water supplies can lead to Giardia infections. Cats can transmit toxoplasmosis, which is dangerous for pregnant women. Others, like malaria, are common in other parts of the world.

If you are traveling, it's important to drink only water you know is safe. Prevention is especially important. There are no vaccines for parasitic diseases. Some medicines are available to treat parasitic infections.

Sexually transmitted infections (STIs), or sexually transmitted diseases (STDs), are infections that are passed from one person to another through sexual contact. They are usually spread during vaginal, oral, or anal sex. But sometimes they can spread through other sexual contact involving the penis, vagina, mouth, or anus. This is because some STIs, like herpes and HPV, are spread by skin-to-skin contact.

Some STIs can be passed from a pregnant person to the baby, either during pregnancy or when giving birth. Other ways that some STIs may be spread include during breastfeeding, through blood transfusions, or by sharing needles.

There are more than 20 types of STIs, including:

• Chlamydia
• Genital herpes
• Gonorrhea
• HIV
• HPV
• Pubic lice
• Syphilis
• Trichomoniasis

STIs can be caused by bacteria, viruses, and parasites.

Most STIs affect both men and women, but in many cases the health problems they cause can be more severe for women. If an STI is passed to a baby, it can cause serious health problems.

STIs don't always cause symptoms or may only cause mild symptoms. So it is possible to have an infection and not know it. And even without symptoms, STIs can still be harmful and may be passed on during sex.

If there are symptoms, they could include:

• Unusual discharge from the penis or vagina
• Sores or warts on the genital area
• Painful or frequent urination (peeing)
• Itching and redness in the genital area
• Blisters or sores in or around the mouth
• Abnormal vaginal odor
• Anal itching, soreness, or bleeding
• Abdominal (belly) pain
• Fever

If you are sexually active, you should talk to your health care provider about your risk for STIs and whether you need to be tested. This is especially important since many STIs do not usually cause symptoms.

Some STIs may be diagnosed during a physical exam or through STI testing. Some tests involve a microscopic examination of a sore or fluid swabbed from the vagina, penis, or anus. Blood tests can diagnose other types of STIs.

Antibiotics can treat STIs that are caused by bacteria or parasites. There is no cure for STIs caused by viruses, but antiviral medicines can often help with the symptoms and lower your risk of spreading the infection.

It's important to get treatment if you have an STI. Some types of STIs can cause serious health problems if they are not treated.

The surest way to protect yourself against STIs is to not have sex.

If you do decide to have sex, you can lower your risk of getting an STI by:

• Having you and your partner tested for STIs before having sex.
• Using a condom every time you have sex. Correct usage of latex condoms greatly reduces, but does not completely eliminate, the risk of catching or spreading STIs. If your or your partner is allergic to latex, you can use polyurethane condoms.
• Reducing your number of sex partners. You might even consider "mutual monogamy" with just one partner. This means that you agree to be sexually active only with them, and they agree to be sexually active only with you. But first you should both get tested to make sure that you don't already have an STI.
• Getting vaccinated against HPV and hepatitis B.

Your skin is your body's largest organ. It has many different functions, including covering and protecting your body. It helps keep germs out. But sometimes the germs can cause a skin infection. It often happens when the germs enter your body through a break, cut, or wound on your skin. Other skin infections can happen in places where the skin rubs together, especially if the area is moist. Infections can also happen when you have a poor blood supply to an area of your body or if your immune system is weakened because of another disease or a medical treatment.

Some skin infections cover a small area on the top of your skin. Other infections can go deep into your skin or spread to a larger area.

Skin infections are caused by different kinds of germs. For example,:

• Bacteria cause cellulitis, impetigo, and staphylococcal (staph) infections
• Viruses cause shingles, warts, and herpes simplex
• Fungi cause athlete's foot and yeast infections
• Parasites cause body lice, head lice, and scabies

You are more likely to get a skin infection if you:

• Have poor circulation
• Have diabetes
• Are older
• Have an immune system disease, such as HIV
• Have a weakened immune system because of chemotherapy or other medicines that suppress your immune system
• Have to stay in one position for a long time, such as if you are sick and have to stay in bed for a long time or you are paralyzed
• Are malnourished
• Have excessive skinfolds, which can happen if you have obesity

The symptoms depend on the type of infection. Some symptoms that are common to many skin infections include rashes, swelling, redness, pain, pus, and itching.

To diagnose a skin infection, your health care provider will do a physical exam and ask about your symptoms. You may have lab tests, such as a skin culture. This is a test to identify what type of infection you have, using a sample from your skin. Your provider may take the sample by swabbing or scraping your skin or removing a small piece of skin (biopsy). Sometimes providers use other tests, such as blood tests.

The treatment depends on the type of infection and how serious it is. Some infections will go away on their own. When you do need treatment, it may include a cream or lotion to put on the skin. Other possible treatments include medicines and a procedure to drain pus.

Your scalp is the skin on the top of your head. Unless you have hair loss, hair grows on your scalp. Different skin problems can affect your scalp.

Dandruff is a flaking of the skin. The flakes are yellow or white. Dandruff may make your scalp feel itchy. It usually starts after puberty, and is more common in men. Dandruff is usually a symptom of seborrheic dermatitis, or seborrhea. It is a skin condition that can also cause redness and irritation of the skin.

Most of the time, using a dandruff shampoo can help control your dandruff. If that does not work, contact your health care provider.

There is a type of seborrheic dermatitis that babies can get. It is called cradle cap. It usually lasts a few months, and then goes away on its own. Besides the scalp, it can sometimes affect other parts of the body, such as the eyelids, armpits, groin, and ears. Normally, washing your baby's hair every day with a mild shampoo and gently rubbing their scalp with your fingers or a soft brush can help. For severe cases, your health care provider may give you a prescription shampoo or cream to use.

Other problems that can affect the scalp include:

• Scalp ringworm, a fungal infection that causes itchy, red patches on your head. It can also leave bald spots. It usually affects children.
• Scalp psoriasis, which causes itchy or sore patches of thick, red skin with silvery scales. About half of the people with psoriasis have it on their scalp.