<unk>  (also known as the seven-year itch) is a contagious skin infestation by the mite Sarcoptes<unk> . The most common symptoms are severe itchiness and a pimple-like rash. Occasionally, tiny burrows may appear on the skin. In a first-ever infection, the infected person will usually develop symptoms within two to six weeks. During a second infection, symptoms may begin within 24 hours. These symptoms can be present across most of the body or just certain areas such as the wrists, between fingers, or along the waistline. The head may be affected, but this is typically only in young children. The itch is often worse at night. Scratching may cause skin breakdown and an additional bacterial infection in the skin.<unk>  is caused by infection with the female mite Sarcoptes<unk>  var. hominis, an ectoparasite. The mites burrow into the skin to live and deposit eggs. The symptoms of<unk>  are due to an allergic reaction to the mites. Often, only between 10 and 15 mites are involved in an infection.<unk>  is most often spread during a relatively long period of direct skin contact with an infected person (at least 10 minutes) such as that which may occur during sex or living together. Spread of the disease may occur even if the person has not developed symptoms yet. Crowded living conditions, such as those found in child-care facilities, group homes, and prisons, increase the risk of spread. Areas with a lack of access to water also have higher rates of disease. Crusted<unk>  is a more severe form of the disease. It typically only occurs in those with a poor immune system and people may have millions of mites, making them much more contagious. In these cases, spread of infection may occur during brief contact or by contaminated objects. The mite is very small and usually not directly visible. Diagnosis is based on the signs and symptoms. A number of medications are available to treat those infected, such as ivermectin or permethrin, crotamiton, and lindane creams. Sexual contacts within the last month and people who live in the same house should also be treated at the same time. Bedding and clothing used in the last three days should be washed in hot water and dried in a hot dryer. As the mite does not live for more than three days away from human skin, more washing is not needed. Symptoms may continue for two to four weeks following treatment. If after this time symptoms continue, retreatment may be needed.<unk>  is one of the three most common skin disorders in children, along with ringworm and bacterial skin infections. As of 2015, it affects about 204 million people (2.8% of the world population). It is equally common in both sexes. The young and the old are more commonly affected. It also occurs more commonly in the developing world and tropical climates. The word<unk>  is from , 'to scratch'. Other animals do not spread human<unk> . Infection in other animals is typically caused by slightly different but related mites and is known as sarcoptic mange.
Scabies
Pediculosis
Pulicosis
Dermatitis herpetiformis
Polymeal
Atopic dermatitis
Malaise
Seborrhoeic dermatitis