What kills a scabies mite? - briefly
Permethrin 5 % cream applied to the entire body and left on for 8–14 hours eliminates the mite, and a single oral dose of ivermectin provides an effective systemic alternative. Other agents such as sulfur ointment or benzyl benzoate also have proven acaricidal activity.
What kills a scabies mite? - in detail
Scabies mites are eliminated primarily through topical acaricides and systemic antiparasitic agents. The most widely recommended 5 % permethrin cream is applied to the entire body from the neck down, left on for ten hours, then washed off. Permethrin disrupts sodium channels in the mite’s nerve membrane, causing paralysis and death. A single application achieves >99 % mortality; a second dose seven days later eradicates newly hatched organisms that survived the first treatment.
Oral ivermectin provides systemic control, especially for crusted scabies or cases where topical therapy is impractical. The standard regimen is 200 µg/kg taken on day 1 and repeated on day 2, with a third dose on day 8 if necessary. Ivermectin binds to glutamate‑gated chloride channels, increasing membrane permeability and leading to paralysis. Efficacy exceeds 95 % when the full course is completed.
Alternative topical agents include benzyl benzoate (25 % solution applied for 24 hours), crotamiton 10 % lotion (applied nightly for five days), and sulfur ointment (5 % in petrolatum applied nightly for three to seven nights). Benzyl benzoate acts as a neurotoxin, while crotamiton interferes with the mite’s sensory receptors. Sulfur exerts a toxic effect through oxidation of the mite’s cuticle.
Environmental decontamination reduces reinfestation risk. Clothing, bedding, and towels should be washed at ≥60 °C or dry‑cleaned. Items that cannot be heated may be sealed in impermeable bags for at least 72 hours, a duration exceeding the mite’s survival without a host. Vacuuming carpets and upholstered furniture removes detached mites and eggs; discarded vacuum bags must be sealed and disposed of.
Resistance to permethrin and ivermectin has been documented in limited regions. In such cases, combination therapy—simultaneous use of a topical agent and oral ivermectin—enhances kill rates. Monitoring treatment response through symptom resolution and, if needed, repeat skin scrapings confirms eradication.
In summary, effective eradication relies on: (1) correct application of a potent topical acaricide, (2) adjunctive oral antiparasitic when indicated, (3) thorough laundering or isolation of personal items, and (4) follow‑up to ensure complete clearance.