Scabies is a contagious skin condition caused by tiny mites that burrow into the skin.
The main symptom of scabies is intense itching that's worse at night. It also causes a skin rash on areas where the mites have burrowed.
Scabies mites are called Sarcoptes scabiei. They feed using their mouths and front legs to burrow into the outer layer of skin (epidermis), where they lay eggs.
After three to four days, the baby mites (larvae) hatch and move to the surface of the skin, where they mature into adults.
Scabies like warm places, such as skin folds, between the fingers, under fingernails, or around the buttock or breast creases. They can also hide under watch straps, bracelets or rings.
How scabies is spread
Scabies is usually spread through prolonged periods of skin-to-skin contact with an infected person, or through sexual contact.
It's also possible – but rare – for scabies to be passed on by sharing clothing, towels and bedding with someone who's infected.
It can take up to eight weeks for the symptoms of scabies to appear after the initial infection. This is known as the incubation period.
Scabies is widespread in densely populated areas with limited access to medical care, and is most common in the following tropical and subtropical areas:
Central and South America
northern and central Australia
In developed countries, scabies outbreaks can sometimes occur in places where there are lots of people, such as schools, nurseries and care homes.
In the UK, most outbreaks of scabies occur in the winter. This may be because people tend to spend more time indoors and closer to each other at this time of year.
It's difficult to know exactly how many cases of scabies there are in the UK. This is because many people don't visit their GP and treat the condition with non-prescription medicines.
Visit your GP if you think you have scabies. It's not usually a serious condition, but it does need to be treated.
The two most widely used treatments for scabies are permethrin cream and malathion lotion (brand name Derbac M). Both medications contain insecticides that kill the scabies mite.
Permethrin 5% cream is usually recommended as the first treatment. Malathion 0.5% lotion is used if permethrin is ineffective.
If your partner has been diagnosed with genital scabies, to avoid reinfection you should visit your nearest sexual health clinic so you can be checked and, if necessary, treated.
Avoid having sex and other forms of close bodily contact until both you and your partner have completed the full course of treatment.
Complications of scabies
Scabies can sometimes lead to a secondary skin infection if your skin becomes irritated and inflamed through excessive itching.
Crusted scabies is a rare but more severe form of scabies, where a large number of mites are in the skin. This can develop in older people and those with a lowered immunity.
Symptoms of scabies
The main symptoms of scabies are intense itching and a rash in areas of the body where the mites have burrowed.
The itching is often worse at night, when your skin is warmer. It may take four to six weeks before the itching starts because this is how long it takes for the body to react to mite droppings.
Symptoms will start within one to two days if you've had a scabies infection in the past. This is because your immune system will have learned to respond to a scabies infection.
The scabies rash consists of tiny red spots. Scratching the rash may cause crusty sores to develop.
Burrow marks can be found anywhere on the body. They're short (1cm or less), wavy, silver-coloured lines on the skin, with a black dot at one end that can be seen with a magnifying glass.
In adults, burrow marks often appear in the following areas:
the folds of skin between fingers and toes
the palms of the hands
the soles and sides of the feet
around the nipples (in women)
around the genital area (in men)
The rash usually affects the whole body, apart from the head. The following areas can be particularly affected:
the underarm area
around the waist
the inside of the elbow
the lower buttocks
the lower legs
the soles of the feet
the shoulder blades
the female genital area
around the ankles
Elderly people, young children and those with a low immune system (immunocompromised) may also develop a rash on their head and neck.
Men usually have one or more very itchy, lumpy, 3 to 10mm spots on the skin of the genitals (on the penis and scrotum).
In infants and young children, burrow marks tend to appear in different places on their body, including on the:
palms of the hands
soles of the feet
Scabies mites leave small red blotches and silver-coloured lines on the skin. These marks are caused by the mites burrowing into the skin.
In infants with scabies, blisters and pustules (small blisters that contain pus) may develop on the soles of the feet and palms of the hands.
Infants with scabies may develop blisters on their feet
Causes of scabies
Scabies is a skin condition caused by the parasite Sarcoptes scabiei.
The intense itching associated with scabies is thought to be caused by the immune system reacting to the mites and their saliva, eggs and faeces.
The scabies mite life cycle
A scabies infestation starts when a female mite burrows into your skin.
Male mites move between different burrow sites looking to mate. After mating, the male mite dies and the female begins to lay eggs, which hatch around three to four days later.
After hatching, the young mites move to the surface of the skin, where they mature into adults after 10 to 15 days. Male mites stay on the surface of the skin, while female mites burrow back into the skin to create a new burrow. The life cycle is then repeated.
Without effective treatment, the life cycle of the scabies mite can continue indefinitely. Scabies mites are resistant to soap and hot water and can't be scrubbed out of the skin.
How scabies is spread
Scabies mites can't fly or jump, which means they can only move from one human body to another if two people have direct and prolonged physical contact.
For example, scabies mites can be transmitted by:
holding hands with an infected person for a prolonged period of time
having sex with an infected person
sharing clothing, towels and bedding with an infected person (although this is rare)
It's unlikely that scabies will be transmitted through brief physical contact, such as shaking hands or hugging.
Scabies mites can survive outside the human body for 24 to 36 hours, making infection by coming into contact with contaminated clothes, towels or bed linen a possibility. However, it's rare for someone to be infected in this way.
Scabies infestations can spread quickly because people are usually unaware they have the condition until two to three weeks after the initial infection.
There's an increased risk of catching scabies in confined environments, such as schools and nursing homes, where people are in close proximity to one another.
Your GP should be able to diagnose scabies from the appearance of your skin, and by looking for the burrow marks of the Sarcoptes scabiei mite.
However, as scabies is spread very easily, it's often possible to make a confident diagnosis if more than one family member has the same symptoms.
Your GP will also want to rule out other skin conditions that may be causing your symptoms, such as eczema or impetigo (a highly contagious bacterial skin infection).
The burrows of scabies mites can be identified by using an ink test. Ink is rubbed around an area of itchy skin before being wiped off with an alcohol pad.
If scabies burrows are present, some of the ink will remain and will have tracked into the burrows, showing up as a dark line.
To confirm the diagnosis, a skin sample may be gently scraped from the affected area so it can be examined under a microscope for evidence of scabies mites, their eggs and faeces (poo).
Visit your GP if you think you have scabies. If you think you have genital scabies or your partner has been diagnosed with it, visit your nearest sexual health clinic, where you'll be examined and, if necessary, treated.
If you decide to treat scabies yourself, you'll need to have a full sexual health check to make sure you don't have any sexually transmitted infections (STIs).
To prevent reinfection, it's important that all members of your household are treated, as well as any sexual partners you've had over the last six weeks (in the case of genital scabies). If you've had genital scabies in the past, anyone you've had sex with in the previous 48 hours will need to be treated.
If you're embarrassed about contacting previous sexual partners, your GP surgery or local sexual health clinic may be able to inform them that they've been exposed to scabies on your behalf without disclosing your identity.
Sexual health clinics
Some sexual health clinics operate on a walk-in basis. Others work by appointment only. It's therefore a good idea to call first.
When you attend a clinic, you'll be asked for your name, date of birth and contact details. These details will be treated confidentially and won't be passed on to your GP without your agreement.
You'll also be asked about your sexual history, including:
when you last had sex
whether you used condoms
whether you've had an STI in the past
whether you're taking any medication
If you're attending a clinic for scabies, you may also be offered tests for STIs.
See your GP immediately if you have scabies and you haven't had a previous infection. Delaying treatment places other people at risk.
As other more serious skin conditions can sometimes cause similar symptoms to the symptoms of scabies, your GP will need to rule these out.
If you have scabies, your partner will also need to be treated regardless of whether or not they have any symptoms. This is because it's highly likely that scabies will have been transmitted through close bodily contact, such as during sex.
To reduce the risk of reinfection, avoid having sex and other forms of prolonged close bodily contact, such as holding hands, until both you and your partner have completed the full course of treatment.
If you've been diagnosed with scabies, you may be advised to visit your nearest sexual health clinic to be checked and, if necessary, treated for other sexually transmitted infections (STIs).
Lotions and creams
Lotions and creams are commonly used to treat scabies. Your GP, pharmacist or nurse will be able to advise you about which treatment to use.
Applying the cream or lotion
To prevent reinfection, all members of your household and any close contacts, including recent sexual partners (see diagnosing scabies for further details), should be treated at the same time as you, even if they don't have any symptoms.
The cream or lotion should be applied to the skin of all of your body, except your head. Before you apply it, make sure your skin is cool and dry. Don't apply it after having a hot bath.
If you apply it when your body is hot, it will quickly be absorbed into your skin and won't remain on the area where the scabies burrows are.
You should also follow the advice outlined below.
Read the patient leaflet that comes with the cream or lotion for details of where to apply it. Some products need to be applied to the whole body, including the scalp and face, whereas others must only be applied from the neck down.
Pay particular attention to difficult-to-reach areas, such as your back, the soles of your feet, in between your fingers and toes, under fingernails, and on your genitals.
Use a cotton bud or old toothbrush to apply the treatment under fingernails and toenails. Put the cotton bud or toothbrush in a bag and throw it away afterwards.
Leave the treatment on your skin for 8 to 24 hours (depending on the preparation used) before washing it off thoroughly. Follow the manufacturer's instructions regarding how long to leave the cream or lotion on for.
Reapply the cream or lotion immediately to any areas of skin that are washed during the period of application.
Wash bed linen, nightwear and towels after the first application.
Repeat the treatment process seven days after the first application to ensure it's successful. The second application will ensure any mites hatched from existing eggs are killed.
Contact your GP if the itching hasn't improved after two weeks of treatment and you notice new burrows on your skin.
It can take a month after treatment for the general itching to subside completely, and longer for the lumpy genital lesions to resolve. Your GP may recommend repeating the treatment or they may prescribe a different lotion.
You should also speak to your GP or pharmacist if you experience any persistent side effects.
On the day you first apply the cream or lotion, you should wash all bed linen, nightwear and towels at a temperature above 50C (122F).
If you're unable to wash certain items, place them in a plastic bag for at least 72 hours. After this time, the scabies mites will have died.
In cases of crusted scabies, you should clean the floors in your house and thoroughly vacuum your carpets and furniture, including the armchairs and sofa.
If you've been diagnosed with scabies, avoid close and prolonged physical contact with others until you've applied the cream or lotion. You should also avoid close contact with other members of your household until their treatment has been completed.
Children and adults can return to school or work after the first treatment has been completed.
Your GP should be able to prescribe treatments, such as a mild steroid cream, to reduce the itchiness. Menthol cream or gel, available from pharmacies without a prescription, may also help relieve itchy skin.
Oral sedative antihistamines are also available from your local pharmacy and can be used to control itching and help you get a better night's sleep.
As this type of antihistamine can cause drowsiness, you should avoid driving or operating heavy machinery if you're affected in this way.
Non-sedating antihistamines don't help relieve the itching of scabies. Check with your GP or pharmacist if you're unsure.
You may continue to experience itchiness for a couple of weeks after your treatment has been completed. This is because your immune system will still be reacting to the presence of dead mites and their droppings.
Visit your GP if you're still experiencing itchiness six weeks after completing your treatment.
Complications of scabies
A secondary infection and crusted scabies are two possible complications of scabies.
Repeatedly scratching itchy skin caused by scabies may break the skin's surface. This will make you more vulnerable to developing a bacterial skin infection, such as impetigo.
Antibiotics may be recommended to control a secondary infection.
Scabies has been known to make some pre-existing skin conditions, such as eczema, worse. However, other skin conditions should settle down after the scabies infection has been successfully treated.
Crusted scabies, also known as Norwegian scabies, is a more severe form of scabies where thousands or even millions of scabies mites are present.
Normal scabies can develop into crusted scabies after a skin reaction. The condition affects all parts of the body, including your head, neck, nails and scalp. However, unlike normal scabies, the rash associated with crusted scabies usually doesn't itch.
In crusted scabies, the increase in the number of mites causes thick, warty crusts to develop on the skin. It's often mistaken for psoriasis (a skin condition that causes red, flaky, crusty patches of skin covered with silvery scales).
Crusted scabies affects people with a weakened immune system (the body's natural defence against infection and illness). This includes:
the very young
people with brain disorders (neurological disorders, such as Parkinson's disease)
people with Down's syndrome
people with a condition that affects their immune system, such as HIV or AIDs
people who are taking steroids to treat other medical conditions
people who are having chemotherapy treatment
Research has found a healthy immune system appears to interrupt the reproductive cycle of the scabies mite. For example, most people with scabies will only have 5 to 15 mites on their body at any one time.
However, if you have a weakened immune system, the number of scabies mites can increase significantly. People with crusted scabies can have thousands or millions of scabies mites on their body at any one time.
Because of the high number of scabies mites, crusted scabies is highly contagious. Even minimal physical contact with a person with crusted scabies, or with their bed linen or clothes, can lead to infection.
However, contact with someone with crusted scabies will only lead to the normal type of scabies in people with a healthy immune system.
Crusted scabies can be treated using insecticide creams or a medicine called ivermectin, which is taken by swallowing a tablet. Ivermectin kills the mites by stopping their nervous system working.