Scabies is an intensely itchy skin condition resulting from an infestation by the microscopic human itch mite, Sarcoptes scabiei var. hominis. These tiny parasites burrow into the top layer of the skin, where they lay eggs and deposit fecal matter. The primary concern for many individuals is understanding how long they might remain contagious after starting treatment.
Treating Scabies Effectively
Effective scabies treatment aims to kill both the mites and their eggs. Physicians typically prescribe topical creams, such as permethrin, a synthetic insecticide that paralyzes and kills mites. This cream is usually applied to the entire body, from the neck down, and left on for 8 to 14 hours before washing.
For widespread infestations or when topical treatments are unsuitable, oral medications like ivermectin may be prescribed. Ivermectin disrupts the nervous system of the mites. Following the full course of treatment is important, often involving a second dose 7 to 14 days later to eliminate newly hatched mites.
When Contagiousness Ends
A person is no longer contagious about 24 hours after successful treatment application. This is due to the rapid action of medications like permethrin and ivermectin, which quickly kill mites. Though mites are eliminated, some symptoms may persist for several weeks.
Itching and a rash can linger for two to four weeks after treatment has successfully killed all mites. This persistence is due to an allergic reaction to the dead mites, their eggs, and fecal material in the skin. Lingering symptoms do not indicate contagiousness or treatment failure. New burrows or intensified itching after several weeks could signal re-infestation or treatment failure.
Beyond Treatment: What to Know
Managing persistent itching after successful scabies treatment can involve using over-the-counter antihistamines or topical corticosteroids. These help alleviate the allergic reaction as skin recovers. Moisturizing the skin also aids healing and reduces irritation.
Environmental cleaning is crucial after treatment to prevent re-infestation. All clothing, bedding, and towels used by the infested person and close contacts in the 72 hours before treatment should be washed in hot water and dried in a hot dryer. Items that cannot be washed, such as stuffed animals or unwashable shoes, should be sealed in a plastic bag for at least 72 hours to a week to kill any remaining mites. If new burrows appear or itching significantly worsens after initial recovery, seek medical attention to rule out re-infestation or incomplete treatment.