Pediculosis

What is Pediculosis?

Pediculosis, or lice infestation, is a condition that impacts hundreds of millions of people around the world every year. It can affect anyone, regardless of where they live or their economic status. Lice are tiny bugs that live only as parasites on humans, meaning they can’t survive off a host. These bugs are passed from person to person through direct contact with skin or personal items, like combs and hats. Symptoms like itching usually don’t appear until about 3 to 4 weeks after infestation.

Humans can be infested by three types of lice: head lice (Pediculus humanus capitis), pubic or crab lice (Pthirus pubis), and body lice (Pediculus humanus). Head lice are the most common and can affect people of all backgrounds. However, body lice are more prevalent among homeless and displaced individuals. Ifyou see signs of scratching and poor hygiene, particularly during the colder months, it’s important to consider lice infestation as a possible cause.

What Causes Pediculosis?

Body and head lice are tiny creatures about the size of 1 to 3 millimeters, while the pubic louse is even smaller. The head louse is a type of parasite that lives all its life on a person’s body. These lice live off the blood they suck from humans. It’s worth noting that lice cannot jump or fly, so they spread only through direct, close contact.

When it comes to head lice, they usually spread when people’s heads touch, or when they share hats or other headwear. They can also spread by contact with objects like movie theater seats where the lice have settled.

Pubic lice are commonly transmitted through sexual contact or through sharing bedding or clothing. As for body lice, they usually stay and lay eggs in clothing or bedding and only go to the skin when they need to feed. Body lice often spread through direct contact, especially among people who have poor personal hygiene. But, they can also spread by sharing clothing, bedding, and towels.

Risk Factors and Frequency for Pediculosis

Research on pediculosis, or lice infestations, is limited and more needs to be done, particularly in areas of the world with high poverty rates and lower healthcare standards. It’s a worldwide issue and no region is immune. Every year, lice infest hundreds of millions of people globally.

• Pediculosis affects between 6 to 12 million people in the United States annually, but the true numbers might be even higher as it’s not a reportable disease.
• Lice outbreaks are mostly found in children aged 3 to 12, and girls tend to be more affected than boys.
• In developed countries, small lice epidemics often occur among schoolchildren, because they have close social interactions that aid the quick spread of lice.
• Multiple family members in the same household often get lice at the same time.
• Lice infestations are more common in warm, humid conditions.
• Head lice can affect anyone, regardless of their social or economic status but body lice are more common among homeless or displaced people, especially during colder months.
• People who are sexually active have a higher risk of getting pubic lice.

Signs and Symptoms of Pediculosis

Pediculosis, or a lice infestation, typically causes itching. The diagnosis is confirmed during a physical check-up by spotting at least one louse. Tools like a bright light, a magnifying glass, or a lice comb can help spot lice. However, misdiagnosis is common. It’s important to know that finding only lice eggs, or ‘nits,’ doesn’t necessarily mean there’s a current infestation because nits can stick to the hair even after successful treatment. Even dandruff and debris from hair spray or dirt can be mistaken for nits.

If lice are found on one family member, all other family members who have been in close contact should also be checked for lice.

Public lice, which are typically found in the pubic hair, are diagnosed the same way, and their presence should trigger a test for other sexually transmitted infections. Similarly, body lice might be suspected in people with itching who live in overcrowded conditions or exhibit signs of poor hygiene.

Testing for Pediculosis

In most situations, doctors can diagnose an infection simply by examining the affected area. An approach they might use is sticking a piece of tape over that area to lift off any adult insects, which can then be studied under a microscope. The eggs, known as nits, are oval and stick strongly to your hair. Another method of detection involves using a special kind of light known as a Wood lamp. Under this lamp, the nits may shine a greenish-yellow color.

Interestingly, sometimes lice are found in the pubic hair, which may suggest the person has a sexually transmitted infection. Additionally, if the diagnosis is not immediately clear, the doctor might take a small sample of your skin (this is called a scraping) to confirm that a fungal infection isn’t to blame for the patient’s symptoms.

Treatment Options for Pediculosis

In the past, head lice were typically removed by either combing the hair with a special lice comb, shaving off the affected hair, or manually picking out the lice. Now, a common practice is called ‘wet combing,’ which means dampening the hair and combing from the hair’s root to the tip using a lice comb. However, the success rate fluctuates with this method.

To tackle lice, medication works in two ways: causing paralysis in the lice or suffocating them by applying treatment to the affected areas. It’s crucial to note that while these treatments effectively kill the lice, they may not always destroy the eggs. Because of this, the treatment often has to be repeated to get rid of all the lice. Usually, a second round of treatment, about a week after the first one, is enough to terminate most nonresistant lice.

There are several approved treatments for lice infestation, such as pyrethroids, malathion, lindane, benzyl alcohol, ivermectin, and spinosad. Among these, pyrethroids, particularly permethrin, are one of the most commonly used treatments for lice. However, there has been some evidence suggesting that lice have been developing resistance to permethrin.

Malathion works well, except it has an unpleasant odor and requires an 8 to 12-hour treatment duration. Similar to malathion, lindane is effective but may have potential for harmful effects on the nervous system. So, it should be used with caution, and its use has even been banned in certain places like California.

Other treatments like benzyl alcohol and spinosad work by essentially suffocating the lice or causing them to become overly excited before paralyzing them. Ivermectin, which is administered both as a lotion and a tablet, is another option, but it is generally less preferred due to its higher cost and the fact that we don’t have as much experience with it.

Oral ivermectin is the only established oral treatment for head lice, but it isn’t approved by the FDA for this purpose. It might be worth considering when the lice are resistant to topical treatments – again, it’s important to note that it also may have a risk of causing harmful effects to the nervous system.

Body lice can generally be gotten rid of by maintaining proper hygiene and washing or treating affected clothing with insecticide. Treating pubic lice is similar to treating head lice, with permethrin and lindane being used- but due to the risk of nervous system damage, lindane should only be used in resistant cases.

As lice can be present on clothing and bedding, one must wash these items in hot water to destroy all stages of lice. The required temperature is 52 degrees Celsius (about 125.6 Fahrenheit) for 30 minutes. Interestingly, certain lice can become heat resistant, sometimes tolnoterating temperatures over 100 degrees Celsius (or about 212 Fahrenheit).

What else can Pediculosis be?

The following conditions might be mistaken for psoriasis because they have similar symptoms:

• Dandruff
• Seborrhea (a skin condition that causes a red, itchy rash and white scales)
• Superficial fungal infection (a type of skin infection caused by a fungus)
• Eczema (a condition that makes your skin red and itchy)
• Folliculitis (inflammation of the hair follicles)
• Scabies (a skin infestation caused by a mite known as the Sarcoptes scabiei)

What to expect with Pediculosis

Generally, dealing with lice infestations has positive outcomes. The medicines used for this are very effective in getting rid of young (nymphs) and adult lice, when used correctly. However, treatment can sometimes fail due to several reasons. These can include the medicine not being able to kill lice eggs (lack of ovicidal activity), failure to remove all live lice eggs (nits), patients not exactly following the treatment – especially not following through with a second treatment in 7-10 days, not applying enough of the anti-lice medicine (duration, amount), not treating people who are in close contact with the patient, not properly cleaning the patient’s environment, and the lice being resistant to the anti-lice medicine (pediculicide).

It’s worth noting that some patients with body lice may develop an infection carried by lice, such as trench fever, typhus, or relapsing/recurrent fever. These, however, are rare.

Possible Complications When Diagnosed with Pediculosis

Facing social embarrassment and missing out on school are some of the impacts that can come with this issue. In addition, damage to the skin could also lead to bacterial infections, like impetigo and pyoderma. Particularly when it comes to body lice, there’s a risk it could lead to certain illnesses, such as trench fever, relapsing fever, and epidemic typhus being passed on to humans.

• Social embarrassment
• Missing school days
• Damage to the skin that can lead to bacterial infections like impetigo and pyoderma
• Risk of transmission of diseases like trench fever, relapsing fever, and epidemic typhus to humans (in case of body lice)

Preventing Pediculosis

The reason why treatments often fail is because patients do not consistently follow the instructions. What’s important is that patients understand the correct way to use their medications, which includes how much to use and for how long. It’s also crucial for them to know that they may need to reapply the treatment about 7-10 days later.

Patients and those caring for them must also know how to handle items like bedding, clothes, and towels which could carry the infestation. These items need to be cleaned with hot water and dried using a high-heat setting. To avoid spreading the infestation, kids and parents must not share things like hats and hair decorations.

To stop a re-infestation of body lice after successfully getting rid of it, personal hygiene and clean clothes are key. At the very least, clothes should be changed and washed properly every week. If a patient has pubic lice, their sexual partners need to be treated too.