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Why can scabies return after a person has already had the infestation?

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skin rash caused by Lyme disease — skin disease Visible alterations in the texture of the skin, such as rashes and hives, can be indicative of serious disease. For example, one of the first signs of Lyme disease is a circular rash in a bull's-eye pattern on the skin.

Scabies can return after an initial infestation because humans do not develop effective or lasting immunity to the itch mite (Sarcoptes scabiei). While most individuals do mount an immunologic reaction to the mite's presence, this response does not provide protection against future infestations, making recurring attacks common.1

Furthermore, reinfestation often occurs because the early stages of the disease may cause no symptoms, allowing an individual to be infested without their knowledge. Because the mite is transmitted through close skin-to-skin contact or via contaminated clothing and bedding, it is essential to treat all members of a household or group simultaneously. If contacts are not treated—regardless of whether they show symptoms—the infestation can easily persist or return.21