Yes. Head lice live on a person, not in the weather: the CDC describes head lice as parasitic insects that usually live on your scalp and feed on human blood, and says adult lice can live on a person’s head for about 30 days. Winter changes what your family wears, not the way lice move from head to head. Here is what cold, heat and a freezer actually do.
Does Cold Weather Kill Head Lice on a Child’s Head?
No. Weather is not how a case of head lice ends: the AAP says the most effective way to treat head lice is with head lice medicine. Where temperature does come up for a nit, it is about distance from the scalp. Lice attach their eggs to hair close to the scalp, and AAP guidance for parents says eggs are usually found within 4 to 6 mm of the scalp and do not survive if they are farther away. The CDC adds that nits cannot hatch and usually die within a week if they are not kept at the same temperature as those found close to the scalp, and that nits attached more than one-quarter inch from the base of the hair shaft are almost always hatched or dead.
Water is a separate question. The CDC says head lice can survive under water for several hours, and our post on whether cold water kills lice goes through it.
Will Below Freezing Temperatures Kill Lice That Fall Off a Head?
A louse that falls off a person dies on its own within a day or two, so freezing it is a step nobody needs. The CDC says lice will die within two days if they fall off a person and cannot feed, and the AAP says they cannot survive more than one day without a blood meal. The CDC’s treatment guidance puts the household risk in proportion: the risk of getting lice from a louse that has fallen onto a rug, carpet or furniture is very small.
For the hats, coats and bedding you cannot wash or dry clean, the CDC and the AAP describe the same move: seal them in a plastic bag for two weeks. The AAP adds that you do not need to throw these items away, and warns that it is dangerous to place anything made of plastic on a child’s head. The CDC says not to use fumigant sprays or fogs, which are not necessary to control head lice and can be toxic if inhaled or absorbed through the skin. The AAP also says not to spray pesticides in your home, and our post on Lysol and lice covers one common household spray.
Does Heat Kill Lice? Where 130 Degrees Fahrenheit Applies
The 130 degrees Fahrenheit the CDC gives belongs to the laundry room: a hot water cycle, a hot dryer, and a soak for combs and brushes, for the items a person wore or used during the two days before treatment. The CDC also says spending much time and money on housecleaning activities is not necessary to avoid reinfestation.
| Situation | What the CDC and the AAP say |
|---|---|
| A louse on the scalp | Head lice feed on human blood, and adult lice can live on a person’s head for about 30 days. |
| A louse that has fallen off a person | It will die within two days if it cannot feed. |
| A nit more than one-quarter inch from the scalp | Almost always hatched or dead; nits cannot hatch and usually die within a week if not kept at the same temperature as those close to the scalp. |
| Clothes, towels and linens used in the two days before treatment | Hot water, 130 degrees Fahrenheit, laundry cycle and high heat drying cycle. |
| Items you cannot wash, plus combs and brushes | Seal items in a plastic bag for two weeks; soak combs and brushes in hot water of at least 130 degrees Fahrenheit for 5 to 10 minutes. |
None of that is a hair-care instruction. For malathion lotion, which it says is flammable and can irritate skin, the CDC says not to smoke or use electrical heat sources, including hair dryers, curlers, and curling or flat irons, and the AAP says to rinse lice medicine off with warm water, not hot water. For flat irons, see our post on whether a flat iron kills lice.
Can You Get Lice in the Winter? What to Check at Home
Yes, because lice spread by contact. The CDC says the most common way to get head lice is by head-to-head contact with a person who already has head lice, and that lice move by crawling and cannot hop or fly. Winter supplies its own shared items, and the CDC’s do-not-share list reads like a winter list: hats, scarves, coats, sports uniforms, hair ribbons and barrettes, along with combs, brushes and towels. The AAP says there is a very small chance head lice will spread by sharing items such as combs, brushes, hats and sports helmets.
Signs can lag behind the lice. The CDC says it may take four to six weeks for itching to appear the first time a person has head lice, and that people with head lice may not have symptoms, particularly with a first infestation or when an infestation is light. The AAP calls regular checks a good way to spot head lice before they have time to multiply, and describes a comb-out check:
- Seat your child in a brightly lit room and part their hair.
- Comb through the hair in small sections with a fine-tooth louse or nit comb.
- Wipe the comb on a wet paper towel after each pass, then examine the scalp, comb and paper towel carefully.
- Start at the hairline at the back of the neck and behind the ears, which the AAP calls the easiest place to find them, then repeat until you have combed all the hair.
Live lice are hard to find, the AAP says, because they avoid light and move quickly, and nits can be confused with dandruff or hair spray droplets. The difference is that nits are firmly attached to the hair and the other particles are not.
Frequently Asked Questions
Will below freezing temperatures kill lice?
Cold is not how a case of head lice ends. The AAP says the most effective way to treat head lice is with head lice medicine, and the CDC says lice that fall off a person and cannot feed die within two days, so a coat does not need a trip to the freezer.
Can you freeze lice and nits on hats or bedding?
There is no need to try. For items that cannot go through a wash, the CDC and the AAP point to a sealed plastic bag for two weeks rather than a freezer. The CDC also suggests vacuuming the floor and furniture, particularly where the infested person sat or lay.
What temperature kills head lice?
For household items the CDC gives 130 degrees Fahrenheit, for laundry water, the high heat drying cycle and a comb soak. For the person with lice the answer is a medicine, not a temperature: the AAP says the most effective way to treat head lice is with head lice medicine.
Do lice die in winter?
On a person’s head, a louse lives for weeks. The CDC says adult lice can live on a person’s head for about 30 days, and the AAP says head lice live about 28 days. The AAP adds that the cycle can repeat every three weeks if head lice are left untreated.
Does heat kill lice and nits?
In the laundry, the CDC’s 130 degree method is the step it gives; on a head, it is a medicine question rather than a temperature one. The AAP says the most effective way to treat head lice is with head lice medicine, and that some products kill lice and eggs while others kill only lice, so whether a lice shampoo kills lice eggs depends on the product. Check with your child’s doctor first.
Can a hot shower kill head lice?
The AAP says the most effective way to treat head lice is with head lice medicine, rinsed off over a sink with warm water, not hot water. The CDC says getting head lice is not related to cleanliness of you or your environment, and the AAP says lice attach to anyone’s hair, clean or dirty. For more, see our post on whether a hot shower kills head lice.
How Lice Lifters of Mercer County Can Help
If the scratching will not settle, or you want an answer instead of another guess, our clinic can check the whole family in one place. Our professional lice treatment is non-toxic and finishes in one visit, and we hold same-day appointments for families who would rather not wait. Our 30 Day Guarantee applies when the whole family is checked. Bring the people who share a bed with your child too: the CDC says to check all household members and other close contacts, and to treat everyone infested at the same time. Telling a nit from a flake of dandruff is the kind of question a second set of eyes can settle, so book a head check when you are ready.
