Scabies ("the itch") is an infestation of the skin by the mite Sarcoptes scabiei that results in an intensely pruritic eruption with a characteristic distribution pattern.
The incidence of scabies undergoes cyclical fluctuations on a worldwide basis, although all parts of the globe are not necessarily in the same phase of the cycle at the same time. In the 1960s the incidence in Europe and North America began to increase, and by 1980 had reached near-pandemic levels. Since then, the rate of scabies has declined somewhat, but the disease is still common. As many as 300 million people may be affected worldwide .
Crowded conditions increase the prevalence of scabies in the population, and scabies can occur in epidemics in institutional settings . In temperate climates, scabies is more common in the winter than the summer probably due to both greater physical crowding in the winter and because mites can survive longer on fomites in colder temperatures .
Transmission of scabies is usually from person to person by direct contact . Transmission from parents to children, and especially from mother to infant, is routine. Schools do not ordinarily provide the level of contact necessary for transmission. In young adults, the mode of transmission is usually sexual contact.
In typical conditions, mites can survive off a host for 24 to 36 hours . They can survive much longer in colder conditions with high relative humidity [3,4]. Under comparable conditions, female mites (which burrow into the skin and cause disease) survive longer than their male counterparts .