How long can lice live on bedding?

The Life Cycle of Head Lice

Stages of Lice Development

«Nits»

Nits, the eggs laid by head‑lice, can remain viable on mattresses, pillowcases, and blankets for several weeks. The egg shell protects the embryo from desiccation, allowing it to survive without a host until the optimal temperature and humidity conditions trigger hatching. Under typical indoor conditions—ambient temperature between 20 °C and 30 °C and relative humidity above 50 %—nits can stay dormant for up to 10 days before the nymph emerges, but they may persist longer if the environment remains moist and warm.

Key factors influencing nit longevity on bedding:

Temperature: Higher temperatures accelerate embryonic development; lower temperatures prolong dormancy.
Humidity: Moisture levels above 50 % support egg survival; dry air hastens desiccation.
Material composition: Fibrous fabrics retain moisture, extending viability, whereas smooth, synthetic surfaces dry more quickly.
Cleaning practices: Regular laundering at 60 °C or higher, or the use of steam, destroys nits; untreated bedding permits continued survival.

Effective control requires immediate removal of contaminated linens, thorough washing, and, when necessary, application of heat or chemical treatments designed to penetrate the protective shell. Failure to address these variables allows nits to hatch and re‑infest the host within the same environment.

«Nymphs»

Nymphs, the immature stage of head lice, emerge after the egg (nit) hatches and must obtain a blood meal within hours to continue development. On a mattress, pillowcase, or blanket, a nymph can survive without a host for a limited period, dictated primarily by temperature and humidity.

In optimal indoor conditions (20‑25 °C, 50‑70 % relative humidity), a nymph may remain alive for 24–48 hours before desiccation or starvation becomes fatal.
At lower humidity (<30 %), survival time drops to 12–18 hours because the insects lose moisture rapidly.
Elevated temperatures above 30 °C accelerate metabolic rate, shortening the viable window to roughly 8–12 hours.
In cooler environments (below 15 °C), metabolic activity slows, allowing nymphs to persist up to 72 hours, though they remain inactive and vulnerable to death from cold stress.

Nymphs require a blood meal within this timeframe; without feeding, they cannot molt to the next stage and will die. Consequently, the presence of nymphs on bedding indicates recent infestation activity, and prompt laundering of linens at high temperature (≥60 °C) is essential to eliminate them before they mature.

«Adult Lice»

Adult lice require a human host for blood meals; they cannot obtain nourishment from fabric. Consequently, their lifespan off a person is limited.

Maximum survival without a host: 24–48 hours under optimal conditions (moderate temperature, high humidity).
Survival declines sharply at temperatures below 15 °C or above 35 °C.
Low humidity (under 30 %) reduces viability to less than 12 hours.
Direct sunlight or exposure to ultraviolet light accelerates desiccation, shortening survival to a few hours.

These parameters define the period that adult lice can remain viable on bedding after detaching from a person. Prompt laundering at ≥60 °C or exposure to a dryer on high heat eliminates any remaining insects. Vacuuming and sealing items in plastic bags for at least 48 hours also prevents re‑infestation.

Survival of Lice Off-Host

Factors Affecting Off-Host Survival

«Temperature»

Lice survive on linens only under conditions that support their metabolic activity. Ambient temperature is the principal factor determining the length of their viability.

At temperatures below 10 °C (50 °F), lice enter a dormant state and die within 24 hours.
Between 10 °C and 20 °C (50 °F–68 °F), survival extends to 2–3 days, but reproduction does not occur.
Within the optimal range of 20 °C to 30 °C (68 °F–86 °F), adult lice remain active for up to 7 days, and nymphs may emerge from eggs.
Temperatures above 30 °C (86 °F) accelerate desiccation; most lice perish within 48 hours, though egg viability may persist for an additional day.

Heat treatment of bedding at 60 °C (140 °F) for at least 30 minutes guarantees complete elimination of both lice and their eggs. Conversely, freezing at –20 °C (–4 °F) for 24 hours also ensures total mortality.

«Humidity»

Humidity significantly influences the survival of head‑lice (Pediculus humanus capitis) when they are detached from a host and remain on fabric. At relative humidity (RH) above 70 %, lice retain moisture and can survive for up to 48 hours on bedding. Below 40 % RH, desiccation occurs rapidly, reducing survivability to 6–12 hours. Temperature interacts with humidity; at 20–25 °C the described time frames apply, while higher temperatures accelerate moisture loss.

The relationship can be summarized:

RH ≥ 80 % – maximum survivability, 48–72 hours.
RH 70–79 % – typical survivability, up to 48 hours.
RH 50–69 % – moderate survivability, 24–36 hours.
RH 30–49 % – reduced survivability, 12–18 hours.
RH < 30 % – minimal survivability, 6 hours or less.

Control measures that lower ambient humidity in sleeping areas—such as dehumidifiers or adequate ventilation—shorten the period lice remain viable on sheets, decreasing the risk of re‑infestation after treatment.

«Food Source Availability»

Lice survive on bedding only while a blood source is reachable. Their diet consists exclusively of human blood; without a host, they cannot feed. The amount of available food determines the maximum period they remain viable.

When bedding is in direct contact with a person, lice may obtain a brief meal from skin exposure or from blood traces left on sheets. In such circumstances, survival can extend to 48–72 hours, because intermittent feeding sustains metabolic functions. If the bedding is removed from the host, residual blood on fabric provides a limited nutrient pool that may support a few additional days, but the lack of fresh meals quickly depletes energy reserves.

Key factors influencing food source availability on bedding:

Presence of a live host nearby (e.g., a sleeping individual)
Amount of blood or serum residues embedded in fibers
Frequency of host‑bedding contact (continuous vs. occasional)
Ambient temperature and humidity, which affect metabolic rate

In the absence of any blood source, adult lice typically die within 24–48 hours, while nymphs, which have lower energy demands, may persist up to 72 hours before starvation becomes fatal. Consequently, the limited food supply on bedding sharply restricts lice longevity.

«How Long Lice Survive on Bedding»

«Adult Lice Survival on Bedding»

Adult head lice (Pediculus humanus capitis) can remain alive on sheets, pillowcases, and blankets for a limited period without a human host. Under typical indoor temperatures (20‑25 °C) and relative humidity of 40‑60 %, an adult louse survives approximately 24‑48 hours. Survival time shortens markedly at temperatures above 30 °C or below 10 °C, where mortality occurs within 12‑24 hours.

Key factors influencing longevity on bedding:

Temperature: Higher heat accelerates dehydration; lower temperatures reduce metabolic activity but do not extend survival beyond two days.
Humidity: Moist environments prolong life by slowing desiccation; extremely dry conditions cause death within 12 hours.
Access to food: Absence of a blood meal triggers starvation; adult lice cannot feed for more than 48 hours.
Surface texture: Smooth fabrics provide less shelter than woven materials, reducing the time lice can hide and retain moisture.

Cleaning measures that eliminate viable adults include washing linens at a minimum of 60 °C for 30 minutes or applying a certified dry‑heat treatment for at least 30 minutes. If laundering is not feasible, sealing items in a plastic bag for 72 hours deprives lice of a host and ensures complete mortality.

«Nymph Survival on Bedding»

Nymphs, the immature stage of head lice, can remain viable on sheets, pillowcases, and other bedding without a blood meal. Survival depends on temperature, humidity, and the time elapsed since the last host contact.

At 68‑72 °F (20‑22 °C) and relative humidity above 50 %, nymphs may live up to 48 hours.
In cooler environments (below 60 °F or 15 °C) activity slows, reducing survivability to 12‑24 hours.
High humidity (70‑80 %) extends the window, allowing survival up to 72 hours.
Low humidity (below 30 %) accelerates desiccation, limiting life to 6‑12 hours.

Feeding is mandatory; nymphs cannot molt to the adult stage without a blood source. If a host does not return within the survival window, the nymph will die from dehydration or starvation. Consequently, prompt laundering of bedding at temperatures of 130 °F (54 °C) or higher eliminates any remaining nymphs.

«Nit Survival on Bedding»

Nit (lice egg) survival on bedding depends on temperature, humidity, and the presence of a host. Under optimal conditions—ambient temperature between 20 °C and 30 °C and relative humidity above 70 %—eggs can remain viable for up to 10 days without a human. At lower temperatures (below 15 °C) or reduced humidity (under 50 %), viability declines sharply, limiting survival to 2–4 days.

Key environmental factors:

Temperature: 20–30 °C prolongs egg development; each 5 °C drop reduces survival time by roughly 30 %.
Humidity: Above 70 % maintains egg moisture; below 50 % accelerates desiccation.
Airflow: Stagnant air preserves moisture; strong ventilation hastens drying.
Surface material: Porous fabrics (e.g., cotton) retain moisture longer than synthetic fibers, extending egg lifespan.

Practical implications:

Immediate laundering: Wash bedding at ≥60 °C and tumble‑dry on high heat to destroy eggs.
Isolation: Store infested linens in sealed plastic bags for at least 7 days; eggs will not hatch without a host.
Environmental control: Reduce bedroom humidity to 40–50 % and maintain cooler temperatures to limit egg viability.

Overall, lice eggs cannot persist indefinitely on mattresses or sheets; they typically lose viability within a week under standard household conditions, and within a few days when environmental parameters are unfavorable.

Preventing Lice Transmission via Bedding

«Recommended Cleaning Practices»

«Washing and Drying Bedding»

Lice can remain viable on sheets, pillowcases, and blankets for several days if conditions are favorable. Prompt laundering eliminates the insects and any viable eggs.

Effective laundering requires water at a minimum of 130 °F (54 °C) for at least 10 minutes, combined with a standard detergent. The temperature must be sustained throughout the wash cycle; lower temperatures allow lice and nits to survive.

Drying must follow washing. Heat above 130 °F for a minimum of 30 minutes destroys remaining stages. A tumble dryer set to high heat accomplishes this; line‑drying in direct sunlight for several hours provides a comparable effect, but indoor drying may be insufficient.

Recommended procedure

Separate bedding from other laundry.
Wash on hot cycle (≥130 °F) with detergent.
Immediately transfer to dryer; set to high heat for ≥30 minutes.
If dryer unavailable, expose bedding to direct sunlight for ≥4 hours.
Store cleaned bedding in a sealed container until use.

Adhering to these parameters reduces the risk of lice re‑infestation from contaminated bedding.

«Vacuuming and Cleaning Surfaces»

Lice can remain viable on sheets, pillowcases, and mattress covers for several days without a host. Their survival time is limited by temperature, humidity, and exposure to mechanical removal. Vacuuming and surface cleaning directly reduce the number of viable insects and interrupt the life cycle.

Regular vacuuming with a high‑efficiency filter extracts adult lice, nymphs, and eggs from fabric fibers and surrounding floor areas. The suction force dislodges insects hidden in seams and folds, while the filter prevents re‑contamination. For optimal results, follow these steps:

Use a vacuum equipped with a HEPA filter.
Run the machine over all bedding surfaces, mattress edges, and headboard at a slow, deliberate speed.
Repeat the process after 48 hours to capture newly hatched nymphs.
Dispose of the vacuum bag or clean the canister immediately to avoid re‑release.

Cleaning hard surfaces near the sleeping area—such as nightstands, lamp bases, and floorboards—eliminates stray lice that have fallen or been transferred by clothing. A detergent‑based solution or a 70 % isopropyl alcohol spray applied to these surfaces kills any insects present and removes their adhesive secretions.

Combining thorough vacuuming with routine surface sanitation shortens the period lice can persist on bedding, lowering the risk of re‑infestation and supporting overall control efforts.

«Items to Pay Attention To»

«Pillows and Blankets»

Lice are obligate ectoparasites that require a human host for feeding, but they can survive off‑host for limited periods. Their ability to persist on household textiles depends on temperature, humidity, and the material’s structure.

Pillows provide a relatively soft, insulated environment. Under typical indoor conditions (20‑25 °C, 40‑60 % relative humidity), adult head lice can remain viable for 24–48 hours. Nymphs and eggs (nits) are less tolerant; they generally lose viability within 12–24 hours. Extreme dryness or heat reduces survival to a few hours.

Blankets, especially those made of dense fibers such as wool or fleece, retain moisture longer than cotton sheets. This moisture retention extends lice survival, allowing adults to live up to 48–72 hours. Nits on blankets may survive slightly longer, up to 48 hours, but do not hatch without a host.

Factors influencing off‑host lifespan:

Ambient temperature: above 30 °C accelerates desiccation; below 15 °C slows metabolism but shortens survival.
Relative humidity: 50‑70 % supports longer viability; below 30 % leads to rapid dehydration.
Material porosity: tightly woven fabrics trap humidity, extending survival; smooth, low‑pile fabrics promote faster drying.

Effective mitigation includes washing pillows and blankets in hot water (≥ 60 °C) for at least 30 minutes, followed by high‑heat drying, or sealing items in airtight bags for a minimum of two weeks to ensure all lice and nits perish. Regular vacuuming of upholstered surfaces removes detached insects and reduces reinfestation risk.

«Stuffed Animals and Fabric Items»

Lice survive on fabric surfaces only as long as they can obtain moisture and warmth. On stuffed animals, blankets, pillowcases, and similar items, adult head‑lice can remain alive for up to 48 hours if temperature stays near body heat (around 30 °C) and humidity is high. Nymphs, which are smaller and more vulnerable, typically die within 24 hours under the same conditions.

Factors influencing survival:

Temperature: Below 20 °C, lice become inactive and die within 12–24 hours. At 30 °C, they retain activity longer.
Humidity: Relative humidity above 70 % extends survival; dry air accelerates desiccation.
Host availability: Without a blood meal, lice cannot reproduce and lose energy quickly.

Practical implications for household items:

Stuffed animals: If an infested child sleeps with a plush toy, the toy can harbour live lice for up to two days. After that period, most insects are dead, but eggs (nits) may remain attached to fibers.
Fabric bedding: Sheets, pillowcases, and blankets can retain live lice for a similar 48‑hour window. Nits attached to fibers can survive longer, up to a week, awaiting hatching conditions.

Control measures:

Wash all washable fabrics in water ≥ 55 °C (130 °F) for at least 10 minutes.
Dry on high heat for a minimum of 20 minutes; heat kills both lice and nits.
Seal non‑washable items in a sealed plastic bag for 14 days; lice cannot survive beyond this period without a host.
Vacuum upholstered furniture and stuffed toys, then discard the vacuum bag or clean the canister.

Understanding these survival limits helps limit re‑infestation risk by ensuring that contaminated fabrics are treated within the time frame lice can remain viable.

Dispelling Common Myths

«Lice Can Jump or Fly»

Lice are wingless insects that move only by crawling. Their legs enable rapid locomotion across hair and fabric, but they lack the anatomical structures required for jumping or flight. Consequently, they cannot disperse through the air or leap from one surface to another.

Because lice cannot fly or jump, their presence on bedding depends on direct contact with an infested person. When removed from a host, they survive by feeding on residual blood and by conserving moisture. Survival time varies with environmental conditions:

Room temperature (20‑25 °C) and moderate humidity (40‑60 %): up to 48 hours without a host.
Lower temperatures (below 15 °C): survival decreases to 12‑24 hours.
High humidity (above 70 %): survival may extend to 72 hours, but only if a blood source remains available.

These limits reflect the insect’s inability to relocate independently. Transfer between bedding and a new host occurs only when a person lies on the contaminated fabric, allowing the louse to crawl onto the scalp. The misconception that lice can fly or jump leads to overestimation of their spread through bedding alone. In reality, without direct host contact, lice die within a few days, making prompt laundering and isolation of infested linens an effective control measure.

«Lice Prefer Dirty Hair»

Lice thrive in environments where scalp oil and debris accumulate. Hair that is infrequently washed retains more sebum and detritus, providing a nutrient‑rich habitat that supports egg‑laying and nymph development. Consequently, individuals with unclean hair are more likely to host larger infestations, increasing the probability that adult lice or nits will transfer to surrounding fabrics.

When a host is absent, lice can persist on bedding, but survival is limited by external conditions. Research indicates:

At room temperature (20‑22 °C) and moderate humidity (40‑60 %), adult head lice survive 24‑48 hours without a human host.
In cooler environments (below 15 °C), metabolic activity declines, extending survival to approximately 72 hours.
High humidity (above 70 %) can marginally increase longevity, but does not exceed 72 hours.
Eggs (nits) remain viable for up to 7 days if temperature and humidity remain stable, yet they hatch only when contact with a host occurs.

The presence of dirty hair accelerates the cycle of re‑infestation. After a brief period on sheets, lice quickly locate a suitable scalp, especially when hair contains residual oils. Regular laundering of bedding at temperatures of 60 °C or higher eliminates both mobile lice and viable nits, breaking the transmission loop.

«Pets Can Transmit Head Lice»

Pets such as dogs, cats, and small mammals can harbor head‑lice eggs (nits) on their fur. Although adult lice require a human scalp to feed, nits transferred to animal coats may fall onto bedding and become a source of infestation for people sharing the bed.

Lice that detach from a human host survive without blood for a limited period. On fabric surfaces, they remain viable for up to 48 hours, after which dehydration renders them non‑infectious. Consequently, bedding that has been in contact with an infested animal can support lice development for two days before the insects die.

Nits can cling to animal fur and be displaced onto sheets during sleep.
Viable lice persist on bedding for 24–48 hours; beyond this window, they lose the ability to feed.
Warm, humid environments extend survival time; cooler, dry conditions shorten it.
Regular laundering at ≥60 °C (140 °F) eliminates both nits and adult lice.
Vacuuming mattresses and changing pillowcases daily reduces residual contamination.

To minimize risk, wash all bedding used by pets and humans together after each exposure, dry on high heat, and keep animal sleeping areas separate from human sleeping surfaces. Maintaining these practices limits the period during which lice can survive on linens and prevents cross‑species transmission.