Scabies is caused by the microscopic mite
Human scabies is caused by an infestation of the skin by the human itch mite (Sarcoptes scabiei var. hominis). The microscopic scabies mite burrows into the upper layer of the skin where it lives and lays its eggs.
Scabies is highly contagious and is spread by close contact. If untreated, it can last indefinitely. Scabies is not caused by poor hygiene.
Scabies is most commonly passed through prolonged skin-to-skin contact but can also be spread through infested bedding, clothing, furniture, or towels. People who live in crowded quarters or are caregivers in places like nursing homes are at greater risk.
Some immunocompromised, elderly, disabled, or debilitated persons are at risk for a severe form of scabies called crusted, or Norwegian, scabies. Persons with crusted scabies have thick crusts of skin that contain large numbers of scabies mites and eggs.
You also can't usually get scabies from toilet seats. Most of the time, it takes lots of close, personal contact with an infected person for scabies to 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.
Unfortunately, in practice, scabies is largely diagnosed based only on the clinical picture, which may lead to a misdiagnosis. A broad differential diagnosis of scabies can include atopic dermatitis (AD), allergic contact dermatitis, nummular eczema, arthropod bites, dermatitis herpetiformis, etc. (1, 7).
Severe itching (pruritus), especially at night, is the earliest and most common symptom of scabies. A pimple-like (papular) itchy (pruritic) “scabies rash” is also common. Itching and rash may affect much of the body or be limited to common sites such as: Between the fingers.
Scabies mites only live on humans, though, and don't live long on pets, clothing, or furniture. If you have an infestation of scabies, you should treat yourself, all members of the household, and all household items to avoid reinfestation after treatment.
Scabies mites are very contagious. They often spread from person to person while they are sleeping in the same bed, or during other close contact. Scabies should be treated quickly to keep the mites from spreading.
You might also see tiny red or black specks of blood or excrement on your bedding or smell a sweet, musty odor. You can tell you have scabies because you develop a rash that tends to itch only at night.
Permethrin kills the scabies mite and eggs. Permethrin is the drug of choice for the treatment of scabies. Two (or more) applications, each about a week apart, may be necessary to eliminate all mites. Children aged 2 months or older can be treated with permethrin.
It gets its name from the thick crusts of skin that form from large numbers of scabies mites and eggs. Scabies can live on the human body for 1 to 2 months. They can live in bedding or furniture for 2-3 days.
Scabies usually is spread by prolonged skin-to-skin contact with a person who has scabies. Scabies sometimes also can be spread by contact with items such as clothing, bedding, or towels that have been used by a person with scabies, but such spread is very uncommon, with the exception of crusted scabies.
Items like bedding, clothing, and towels used by an infested person can be cleaned by washing with hot water and drying on high heat. For items that cannot be washed, store in a sealed plastic bag for at least 72 hours to kill any mites. Vacuum and clean rooms and furniture used by the person with scabies.
The most common symptoms are: Blisters or bumps — Pink, raised bumps with a clear top filled with fluid are likely to appear on areas of the body where scabies have infested. Itching — A sensation of a foreign object crawling on the skin will create constant and sometimes severe itching, especially at night.
If a person has scabies, how long are they contagious? A person with scabies can pass it on to another person as long as they have not been treated, even if they don't have symptoms. The clothes and bedding of a person with scabies can also be infested with scabies mites until they are properly washed or treated.
The scabies rash takes the form of small, red bumps that may look like pimples, bug bites, hives or knots under the skin. You might be able to see the burrow tracks created by the mites, which appear as raised lines of tiny blisters or bumps. Some people develop scaly patches that resemble eczema.
Scabies is a common disease and typically described as a skin condition with sparing of face and scalp in adults. However, crusted scabies is not conventional scabies. It can also affect the scalp.
Scabies mites do not survive more than 2-3 days away from human skin. Items such as bedding, clothing, and towels used by a person with scabies can be decontaminated by machine-washing in hot water and drying using the hot cycle or by dry-cleaning.