What is the strongest treatment for scabies?

The treatment of scabies

Most experienced clinicians will miss the diagnosis of scabies at least once. As a result the patient’s itch and discomfort will be prolonged and additional contacts needlessly infected. Scabies should be excluded in any patient with itch. The history, particularly itching of recent onset, and careful scrutiny of hands and wrists will usually establish the diagnosis. Scabies can be confirmed with skin scrapings. Treatment is effective provided it is done scrupulously. Permethrin cream is preferred in most cases, but severe cases may require oral ivermectin.

Introduction

Scabies is caused by Sarcoptes scabiei, a barely visible mite that is host specific for humans. Sarcoptes mites from other animals may also occasionally infest humans.

Mite movement is temperature dependent. The mite is almost immobilised below 20?C. Transmission of mites between humans is therefore increased in a warm environment. Human to human contact of about 20 minutes allows the mite to transfer. Transmission also occurs via contaminated clothing, bedding, furniture and contaminated epithelial debris shed from scabetic patients.

The intraepidermal burrow is the pathognomonic clinical sign of scabies and contains the pregnant female mite, eggs, faeces and other discarded material from the mites. The eggs hatch in two weeks. The larvae form intraepidermal lesions whilst they mature into the adult form. This maturation takes only 2-3 weeks. Most humans develop a stable population of between 10-50 pregnant females in an ongoing infestation. Some forms of scabies have thousands of mites and are highly contagious.

Clinical settings

Scabies in the family setting usually means one or two other members of the family will also be affected. These patients usually have a low mite count (10-50) and appropriate treatment of the whole family is curative. In extended families, contact tracing is important to make sure that relatives and other people who had significant physical contact with the infested patient are also treated.

Scabies in a nursing home or institution is a difficult problem. The patients may be disabled, immobile or otherwise compromised and often have high mite counts. As a result they are more infectious. Nursing staff and patients in the surrounding areas will often become infected. Minor epidemics then result. The scabies may become long-standing despite treatment. Extensive contact tracing and treatment of affected patients and the immediate environment are therefore important.

Some patients develop severe scaling and crusting as a result of the infestation and have tens of thousands of mites. This has been described as Norwegian scabies (probably because it was first reported in Norway in 1848 when it was thought to be an endemic form of leprosy). Discarded crust and scale in bedding has hundreds of potentially infectious mites. Treating the patients’ environment is particularly important.

Clinical features

Scabies should be considered in any patient with an unexplained itch of recent onset (Table 1). A definite diagnosis can be made with recognition of one major criterion (Table 2) and a likely diagnosis can be made with two or more of the minor diagnostic criteria.

Itch
Itch is the predominant feature in all but the most compromised patients. The itchy rash begins about four weeks after the beginning of the infestation coinciding with sensitisation. It is often worse at night.

When should I think about scabies?

Unexplained pruritus especially if other contacts are also itchy

`Atopic or irritant dermatitis’ of very recent onset

Persistent insect bite reactions

Recurrent impetigo with itch

Pustular lesions on the palms and soles particularly in the young

Unusual pruritic psoriasiform rashes that are crusted and scaling or blistering

Diagnosis

• Identifiable typical burrow particularly associated with itchy rash
• Positive skin scrapings showing eggs or mite or faeces

Minor criteria (two needed for likely diagnosis)

Wrist showing lesions and intraepidermal burrow of the scabies mite

The itch is due to a combination of non-specific factors and specific immunological events as patients develop hypersensitivity to the mite and its products. A prickling irritation can be felt when mites move around on the warm skin.

Secondary dermatitis is widespread due to these immunological mechanisms, scratching and the irritation caused by the treatments applied by an increasingly desperate itchy patient.

Burrows

The diagnostic sign of scabies is the burrow (see picture). This is an intraepidermal track made by the egg laying female and is usually less than a centimetre long. The opening of the burrow may have a mild scale while the blind end contains the female. Most adult humans will have a burrow on the hands or wrists. Children will often have burrows on the feet as well. Burrows may also be found at other sites.

Other presentations

Atypical clinical features are less common. Patients may develop urticarial or blistering rashes if they are very hypersensitive to the mite. Nodular lesions may develop from chronic scratching and infestation. Children may have a pustular eruption particularly around their hands and feet.

Investigations

In most patients, scraping a number of burrows will reveal the mite, eggs or faeces. This confirms the diagnosis and is a major diagnostic criterion (Table 2).

Treatment

There are some general principles (Table 3), but the treatment is influenced by the clinical setting.

General strategies in scabies management

Confirm the diagnosis preferably by identifying a typical burrow or positive skin scrapings.

Trace all contacts and ensure appropriate treatment.

Apply antiscabetic cream thoroughly. This usually means the entire body from the neck down. In some individuals the head must also be treated. Repeat in one week.

Treat all contaminated clothing and bedding. In some circumstances the immediate environment may also need decontamination.

Follow up 4-6 weeks later to ensure clearance.

Treatment of household scabies

• Treat the whole family simultaneously, even members who are not itchy. The initial strategy is to kill the mite. Once this is achieved then treatment for the itch and dermatitis can begin.
• Apply the acaricidal preparation to dry skin from the neck down emphasising treatment of all sites — e.g. under nails, soles of feet, natal cleft. Permethrin cream is a good primary treatment and the author advises patients to leave this on for 24 hours. The head requires treatment if involved. This should be looked for in the elderly, infants, compromised patients and those with Norwegian scabies.
• Family members with likely scabies should have a repeat permethrin treatment in one week.
• Wash all clothes and bed sheeting being used in hot water and either iron or put through a hot dryer. An alternative is to store bedding and clothing for 1-2 weeks.
• Advise patients that `mite killing’ cream will not immediately resolve the itch or the rash.
• Begin antipruritic dermatitis treatment immediately after each course of antiscabetic creams: (a) moisturise before and after showering (b) avoid irritants such as too much soap and excessive sweating (c) apply appropriately potent topical corticosteroids to the rash for the next 2-3 weeks (d) treat secondary infection

Family (Table 4)

An inviolable principle of scabies treatment is to treat all significant contacts. In practice this means all members of the family should have at least one treatment. Patients with definite or probable scabies should have two treatments. Caution should be exercised in treating infants, pregnant or lactating women, and the very elderly, as some preparations may be more toxic.

The treatment choice rests largely between topical permethrin or lindane applied to the skin. Permethrin is preferred because of its apparent lesser toxicity. A large number of other agents may be used in special circumstances (Table 5). The application must be done scrupulously. If one burrow is spared then the infestation will persist. The cream therefore needs to be massaged under nails and reapplied to any areas that are washed.

Antiscabetic treatment

The potential for neurotoxicity limits the use of this agent particularly in infants, pregnant and lactating women, and in the elderly.

Permethrin Topical

Permethrin is used to treat scabies (‘mites that attach themselves to the skin) in adults and children 2 months of age and older. Over-the-counter permethrin is used to treat lice (small insects that attach themselves to the skin on the head) in adults and children 2 months of age and older. Permethrin is in a class of medications called scabicides and pediculicides. It works by killing lice and mites.

How should this medicine be used?

Permethrin comes as a cream to apply to the skin. Over-the-counter permethrin comes as a lotion to apply to the scalp and hair. Permethrin cream is usually applied to the skin in one treatment, but occasionally a second treatment is necessary. Permethrin lotion is usually applied to the skin in one or two treatments, but occasionally three treatments are necessary. If live mites are seen two weeks (14 days) after the first treatment with permethrin cream, then a second treatment should be applied. If live lice are seen one week after the first treatment with over-the-counter permethrin lotion, then a second treatment should be applied. Follow the directions on your prescription label or the package label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Use permethrin exactly as directed. Do not use more or less of it or use it more often than prescribed by your doctor.

Permethrin should only be used on the skin or hair and scalp. Avoid getting permethrin in your eyes, nose, ears, mouth, or vagina. Do not use permethrin on your eyebrows or eyelashes.

If permethrin gets in your eyes, flush them with water right away. If your eyes are still irritated after flushing with water, call your doctor or get medical help right away.

To use permethrin cream, follow these steps:

1. Apply a thin layer of cream all over your skin from your neck down to your toes (including the soles of your feet). Be careful to apply cream in all skins folds, such as between your toes and fingers or around your waist or buttocks.
2. For treatment of babies or adults over 65 years of age, the cream should also be applied to the scalp or hairline, temples, and forehead.
3. You may need to use all of the cream in the tube to cover your body.
4. Leave the cream on your skin for 8-14 hours.
5. After 8-14 hours have passed, wash off the cream by bathing or showering.
6. Your skin may be itchy after treatment with permethrin cream. This does not mean your treatment did not work. If you see live mites 14 days or more after treatment, then you will need to repeat the treatment process.

To use the lotion, follow these steps:

1. Wash your hair with shampoo and rinse with water. Do not use a conditioner or a shampoo that contains a conditioner because your treatment will not work as well.
2. Dry your hair with a towel until just damp.
3. Shake permethrin lotion well right before use to mix the medication evenly.
4. Use a towel to cover your face and eyes. Be sure to keep your eyes closed during this treatment. You may need to have an adult help you apply the lotion.
5. Apply permethrin lotion to your hair and scalp area. Begin to apply the lotion behind your ears and at the back of your neck and then cover all of the hair on your head and scalp.
6. Keep the lotion on your hair and scalp for 10 minutes after you finish applying permethrin lotion. You should use a timer or clock to track the time.
7. Rinse your hair and scalp with warm water in a sink. You should not use a shower or bathtub to rinse the lotion away because you do not want to get the lotion over the rest of your body.
8. Dry your hair with a towel and comb out tangles.
9. You and anyone who helped you apply the lotion should wash your hands carefully after the application and rinsing steps.
10. A lice comb may also be used to remove the dead lice and nits (empty egg shells) after this treatment. You may also need to have an adult help you to do this.
11. If you see live lice on your head 7 days or more after treatment, repeat this entire process.

After using permethrin, sanitize all the clothing, underwear, pajamas, hats, sheets, pillowcases, and towels you have used recently. These items should be washed in very hot water or dry-cleaned. You should also wash combs, brushes, hairs clips and other personal care items in hot water.

Ask your pharmacist or doctor for a copy of the manufacturer’s information for the patient.

Scabies

Scabies is caused by the Sarcoptes scarbiei mite. It causes a rash so itchy that it interrupts sleep. It can be treated with certain ointments or pills.

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Overview

What is scabies?

Scabies is a skin condition caused by the Sarcoptes scabiei var hominis mite. These little bugs make tunnels (burrow) under your skin and cause small red bumps and severe itching. Scabies spreads easily from person to person, especially among people who live close together. If one family member has scabies, a provider should check and treat other family members and close contacts at the same time.

Scabies is a worldwide problem but happens most often in tropical areas and in very crowded places.

Scabies is also known as sarcoptic mange. Animals can also get scabies, but the mites are slightly different. Usually, the mites that affect pets can’t adapt to living on humans. However, you might have some type of reaction to mites on your pet.

Where do scabies mites live on your body?

The mites live in the folds and narrow cracks of your skin. Common mite sites include:

• Folds in between the fingers and toes.
• Folds in your thighs and genital area.
• Bends at your wrists and knees.
• The area around your waist.
• Under fingernails.
• Under rings, watch bands and bracelets.
• The area around your nipples.

Who gets scabies?

Anyone can get scabies. It’s not a disease caused by poor hygiene. Some people are more likely to get scabies, including:

• People who live in close, crowded conditions.
• Infants and children. (Children have a lot of close physical contact with their parents, friends, family members and classmates.)
• People who are elderly, especially those living in nursing homes.
• Healthcare workers who care for people who aren’t aware they have scabies.

Are there different types of scabies?

Yes, there are different forms in addition to the classic form. Other types include:

• Crusted (Norwegian): This type often happens in people with faulty immune systems. It tends to form crusted areas covering a large area of skin. If you have crusted scabies, you might have millions of mites instead of the 10 to 15 mites common with classic scabies.
• Nodular: This type is more common among children. The brown-red nodules can still be there long after the mites are gone.
• Bullous: In adults, this type of scabies can be mistaken for bullous pemphigoid, another condition involving skin blisters.
• Scalp: This type occurs on your scalp and may not present symptoms except for scales that may look like psoriasis.

Symptoms and Causes

What are the symptoms of scabies?

You can be infected with scabies for four to six weeks before having the early symptoms of the red rash and bumps. The tiny spots might look like bumps or pimples.

The rash spreads slowly over a period of weeks or months. In addition to the rash, signs and symptoms of scabies include:

• Intense itching, which is worse at night and could make it hard to sleep.
• Bumps that sometimes become infected as a result of scratching.
• A later rash that looks grayish or skin-colored lines on the skin.

Children with scabies may have itching all over their bodies and might be cranky or tired from lack of sleep due to itching at night.

Diagnosis and Tests

How can I know if I or my child has scabies?

If you think you or your child has scabies, make an appointment with your healthcare provider. Most cases of scabies can be confirmed just by looking closely at the skin. Your healthcare provider may also apply mineral oil to the rash and use a scalpel to get a small sample of skin (scraping). The sample is placed under a microscope and examined for mites and mite eggs.

Can I see the mite?

The scabies mite is very small, about the size of the tip of a needle and very difficult to see. It’s white to creamy-white in color. It has eight legs and a round body, which you can see if the mite is magnified.

Management and Treatment

How is scabies treated?

Your healthcare provider must order a cream that contains a medicine called permethrin to treat scabies. The cream is applied to your whole body below your head, including the hands, palms, and soles of the feet.

In children with scabies, the cream may need to be applied to the scalp. Be sure that skin is clean, cool and dry before applying the cream.

Permethrin cream is left on the skin for eight to 14 hours and then washed off. (The cream is most often applied at night and washed off in the morning.)

Ivermectin is another option for treating scabies. This is an antiparasitic pill given in a single dose, followed by a second dose one to two weeks later.

If you’re pregnant or lactating, you shouldn’t use ivermectin. If your child weighs less than 35 pounds (15 kilograms), they shouldn’t use ivermectin.

Your provider might also suggest antihistamines, which can be taken by mouth and as a cream, to relieve itching. Your provider will also treat any type of infection that may be present.

How soon are the mites killed?

The mites that cause scabies are killed after one treatment. The treatment doesn’t need to be repeated unless the infection doesn’t go away or comes back.

How soon does the itching stop?

The itching may take two to four weeks to go away, even though the mites have been killed.

How soon does the scabies rash go away?

Red bumps on the skin should go away within four weeks after treatment.

Prevention

How can I prevent spreading scabies?

You can prevent spreading scabies by:

• Washing bed linens, towels and clothing in hot water and machine dry.
• Making sure family members and others in close contact with the infected person get checked for scabies.
• Limiting close contact with others if you know you’ve got scabies.

Outlook / Prognosis

If my child has scabies, how soon can they return to school?

Your child can return to school the day after treatment.

Can a person get scabies more than once?

Yes. You can get scabies any time that you come into close contact with an infected person.

Living With

When should I see my healthcare provider?

Call your healthcare provider if:

• You’ve been treated for scabies but still have symptoms or skin issues after a month.
• You’ve developed signs of a bacterial infection, like redness or sores with pus. These types of infections can lead to more severe medical issues.
• You have some type of side effect from the medication or the condition that is worrying you.

Frequently Asked Questions

What’s the difference between scabies and eczema?

Scabies and eczema are both skin conditions that give you itchy red rashes. However, scabies is caused by a parasite, a mite that invades your body. Sometimes you can see patterns that look like lines where the burrows are.

Eczema is a type of rash with an unknown cause. It can come and go seasonally. It can show up as red spots or weeping blisters. Unlike scabies, eczema isn’t contagious. Eczema treatments are designed to manage your symptoms. Scabies treatments rid your body of the mites.

If you have a rash that is red and itches, contact your healthcare provider. It’s important to catch scabies as soon as possible so you can get rid of them and not infect other people. If it’s eczema, your provider can suggest remedies that will help your symptoms.

Will scabies go away on its own?

No, scabies won’t go away on its own. If you don’t treat it, you’ll probably continue to spread the disease to other people. In addition, the constant itching will probably lead to constant scratching and will cause some type of bacterial infection of the skin.

Is scabies hard to get rid of?

Scabies is treatable, but they can be hard to get rid of completely. Certain forms of scabies are harder to treat, such as the crusted form. In addition, you might need more than one round of treatment to make sure all of the mites are gone.

A note from Cleveland Clinic

If you have a rash and it’s so itchy that you can’t sleep, make sure you contact your healthcare provider. You may have scabies, which is an infectious disease. You and other people close to you should be tested and treated. You’ll want to contact your healthcare provider if you have any kind of skin rash that doesn’t go away and that causes problems for you. Scabies, like many other types of red itchy rashes, can be treated successfully.