Scabies 

Scabies is a contagious skin condition where the main symptom is intense itching. It is caused by tiny mites called Sarcoptes scabiei, which burrow into the skin.

Scabies can be spread through:

• skin-to-skin contact for long periods of time with someone who is infected
• sexual contact with someone who is infected

Scabies can also be passed on through sharing clothing, towels and bedding with someone who is infected. However, this is less likely than getting the infection through skin-to-skin contact.

The incubation period (the time it takes for symptoms to show after infection) for scabies is up to eight weeks.

How common is scabies?

Scabies is particularly widespread in countries that have a high population density and limited access to medical care. The condition is present in the following tropical and subtropical areas at all times (endemic):

• Africa
• Egypt
• Central and South America
• northern and central Australia
• Caribbean Islands
• India
• Southeast Asia 

In developed countries, outbreaks of scabies can sometimes occur in places where there are lots of people, such as schools, nurseries and nursing homes. There can also be individual cases of scabies that are not isolated to one specific place. These cases are known as sporadic.

It is difficult to estimate the exact number of scabies cases in England and Wales because many people treat the condition themselves using over-the-counter (OTC) medicines, without visiting their GP.

Most outbreaks of scabies in the UK occur during the winter, which may possibly be because people tend to spend more time indoors and are in closer proximity to each other during this time of year. Outbreaks of scabies are also more common in cities.

Scabies mites

Sarcoptes scabiei mites like warmth and smell. The mites feed using their mouth parts and front legs to dig into the outer layer of the skin (epidermis). They ingest tissue and fluids as they burrow.

As the mites feed within the skin layer, they lengthen their burrows horizontally by about 0.5mm a day. The females lay two to three eggs a day inside the burrow. After three to four days, the larvae (baby mites) hatch from the eggs and travel to the surface of the skin where they lie in shallow pockets before maturing into adult mites. 

Scabies like warm places on the skin, such as skin folds, between the fingers, under fingernails or around the buttock or breast creases. They can also hide under watch straps or bracelets, and in the skin on the finger under rings. 

See Scabies – causes for more information about the life cycle of the scabies mite.

Outlook 

Scabies is not usually a serious condition, but the intense itching can be unpleasant and have an adverse effect on a person’s quality of life. However, the itching that is caused by scabies can usually be effectively treated using topical treatments (skin creams).

Scabies can lead to a secondary skin infection if the skin becomes irritated and inflamed through excessive itching.

A more severe, but uncommon, form of scabies can occur in cases where there are a lot of mites in the skin. This is called crusted scabies, and can affect older people and those with a lowered immune system (the body’s natural defence against illness and infection).

See Scabies – complications for more information about crusted scabies.