Scabies is a skin infection caused by a mite. It can be uncomfortable but is not a serious disease.
Scabies mites live on and under the skin. The most common type ‘Classical Scabies’ can only survive off the body for 24 to 36 hours, and the rarer ‘Crusted Scabies’ can survive for 7 days.
Scabies can be associated with overcrowding and poor personal hygiene. The prevalence of scabies is greatest in children and young adults aged 10 to 19 years. It is more common in women, urban areas and during the winter period.
Symptoms take 3 to 6 weeks to develop after infestation if a person has never had scabies. In a person who has had scabies before, the symptoms usually appear much earlier, 1 to 3 days.
- Rash – The appearance of the rash can differ, but tiny pimples and nodules are characteristic
- Burrows are also common which look like thin raised track lines in the skin. The scabies mites are usually attracted to folded skin such as the webs of the fingers but may also be seen on the wrists, palms, elbows, genitalia and buttocks
- Itching – Itching can be intense and is usually worse at night or when warm
- Secondary skin infection can occur if the rash has been scratched
Crusted scabies (also called Norwegian scabies) is characterised by thick crusts of skin that contain large numbers of scabies mites and eggs. It is a severe form of scabies that occurs most often in people who are immunocompromised. The symptoms of the more common form of scabies, such as itching and a rash, may be absent. If Crusted Scabies has been considered it is important that the GP reviews, considers skin scrapings. A diagnosis by a dermatologist is essential.
How is Scabies transmitted?
It is transmitted through prolonged close skin to skin contact, so the risk transmission is higher in families or people who live together (care homes, hostels, day centres etc.) than e.g., schools. The scabies mite does not survive for long outside the human body and cannot usually be picked up just from clothes.
However, Crusted scabies is very contagious and can spread both by direct skin-to-skin contact and through contaminated items such as clothing, bedding, and furniture. The mites can survive in the environment for 7 days, therefore, can easily be transmitted from towels, clothing, bedding and upholstery.
Diagnosis of scabies is usually made from the history and examination of the affected person, in addition to the history of their close contacts. Misdiagnosis is common because of its similarity to other itchy skin disorders, such as contact dermatitis, insect bites and psoriasis.