How can lice and fleas be killed? - briefly
Apply an appropriate insecticide—permethrin or pyrethrin‑based products for lice, and flea sprays or foggers containing adulticides and larvicides for fleas—followed by thorough washing of bedding and clothing in hot water (≥130 °F) and vacuuming of carpets and upholstery. Repeat treatment after 7–10 days to eliminate any newly hatched insects.
How can lice and fleas be killed? - in detail
Lice and fleas are external parasites that require immediate eradication to prevent skin irritation, secondary infections, and disease transmission. Effective control combines direct treatment of the host, thorough sanitation of the environment, and ongoing monitoring.
Chemical agents provide rapid knock‑down. For humans, topical pediculicides containing 1 % permethrin or 0.5 % malathion are applied to the scalp and left for the recommended duration before rinsing. For animal hosts, spot‑on products with fipronil, imidacloprid, or selamectin are administered according to weight. Oral insecticides such as ivermectin may be prescribed when topical options fail, but dosage must follow veterinary guidance.
Physical removal complements chemicals. Fine‑toothed combs, used on wet hair with conditioner, extract lice and nits after each treatment cycle. Flea combs for pets separate adult insects from fur; repeated combing over several days eliminates emerging fleas. High‑temperature laundering—minimum 60 °C—destroys eggs and larvae on clothing, bedding, and linens.
Environmental sanitation targets stages beyond the host. Vacuuming carpets, upholstery, and pet bedding eliminates eggs and pupae; dispose of vacuum bags promptly. Steam cleaning at 100 °C penetrates cracks where fleas develop. Insect growth regulators (IGRs) such as methoprene or pyriproxyfen, applied to cracks and crevices, interrupt the life cycle by preventing maturation of immature stages.
For severe infestations, professional pest‑control services deploy foggers or residual sprays containing pyrethrins or synergists. Application follows label instructions to protect occupants and pets. After treatment, maintain a low‑humidity environment (below 50 %) to inhibit flea development.
Monitoring continues for at least four weeks, the duration of the longest life stage. Re‑examine hosts and surroundings weekly, retreating only if live parasites are observed. Documentation of product names, concentrations, and application dates ensures consistent follow‑up and prevents resistance buildup.