Head lice are small parasitic insects that live exclusively on the human scalp, feeding on blood several times a day. They are a common issue, particularly among school-aged children, but can affect anyone. While the primary concern is the infestation on the head, the possibility of these parasites transferring to household surfaces like bedding often causes worry. Understanding the actual risk and the necessary steps for cleaning is important during an infestation.
Visibility and Identification of Lice on Surfaces
You can potentially see lice on bedding, but finding them there is infrequent. An adult head louse is roughly the size of a sesame seed (2 to 3 millimeters long) and typically appears grayish-white or tan. Nymphs, or young lice, are smaller but still visible to the naked eye. Lice have six claw-like legs adapted for grasping hair shafts, making them reluctant to leave the warm environment of the human head. Objects mistaken for lice or nits on bedding are usually lint, dust, or hair debris, as nits are tiny eggs firmly glued to the hair shaft near the scalp.
Survival Time and Transmission Risk from Bedding
Head lice are obligate parasites, requiring a human host for warmth and blood. Once an adult louse falls onto a surface like bedding, its survival time is very limited without a blood meal. Most adult lice die within 24 to 48 hours off the host, often much sooner.
Transmission from bedding is extremely rare; the primary route is direct head-to-head contact. Nits, the eggs, are less of a concern because they need the consistent temperature near the scalp to develop and hatch. If nits detach and land on a sheet, they become non-viable without the necessary warmth and humidity. The risk of a new infestation starting from a louse that fell onto bedding is minimal.
Essential Cleaning Protocols for Infested Areas
Taking precautionary cleaning steps helps ensure the infestation is contained, even though the risk of transmission from bedding is low. All bedding used by the infested person should be removed and washed. Washing these items in hot water, specifically at 130°F (54.4°C), is sufficient to kill both lice and detached nits. The high-heat drying cycle is effective because the heat dehydrates and kills any remaining parasites; dry items on the highest heat setting for a minimum of 20 minutes.
For non-washable items that contacted the head, such as stuffed animals or pillows, seal them tightly in a plastic bag. Sealing these items for 72 hours, or up to 10 days, ensures any lice or nits die due to a lack of a host.