Yes, you can have head lice for months without knowing, especially with a first-time infestation, because itching (an allergic reaction to saliva) can take 4-6 weeks to develop, and lice are small, fast, and easily mistaken for dandruff. Many people have light infestations with few symptoms, and the only sure way to know is to carefully check the scalp for tiny bugs and their pinhead-sized eggs (nits) stuck to hair shafts.
People who have head lice for the first time may not feel itchy right way. It can take 4 to 6 weeks for itching to start. You may be able to see lice, but they move quickly, avoid lights and are small. You may also see lice eggs on hair shafts.
New eggs hatch after a week (42-70 new bugs over the course of a week). After a week, the hatched nymphs, now adult lice, begin to lay their own eggs. Lice live for about 30 days, having the ability as an adult louse to reproduce after a week which yields 100-200 eggs in its lifetime!
Head lice during pregnancy and breastfeeding can be treated with pediculicides including permethrin, malathion, and ivermectin. There are studies providing evidence that these agents do not increase the risk of birth defects.
Some people may not have symptoms, particularly with the first infestation or when the infestation is light. It may take 4-6 weeks for itching to appear the first time a person has head lice.
There are many other causes of scalp itching that can be mistaken for head lice. These include folliculitis, psoriasis, eczema and dandruff, but they do not have the features mentioned above.
Itching (pruritus) is the most common symptom of head lice infestation. It is caused by an allergic reaction to louse bites. It may take four to six weeks for itching to appear the first time a person has head lice.
Yes, head lice can briefly live and crawl onto pillows after falling off a human host, but they die within 1-2 days without a blood meal from a human scalp, making pillows a low risk for transmission; nits (eggs) won't hatch off the scalp and need heat to survive, so washing bedding in hot water kills them effectively. The main risk is head-to-head contact, not furniture or bedding.
The risk of getting infested by a louse that has fallen onto a carpet or furniture is very small. Head lice survive less than 1–2 days if they fall off a person and cannot feed; nits cannot hatch and usually die within a week if they are not kept at the same temperature as that found close to the scalp.
You cannot prevent head lice
There's nothing you can do to prevent head lice. You can help stop them spreading by wet combing regularly, using a detection comb, to catch them early. Do not use medicated lotions and sprays to prevent head lice.
Infested children usually carry fewer than 20 mature head lice (more commonly less than 10), each of which, if untreated, live for three to four weeks (5–7). Head lice stay close to the scalp for food, warmth, shelter and moisture (6,7).
Getting head lice isn't a sign of poor hygiene or unclean surroundings. Head lice prefer clean hair to attach and lay their eggs. Another common misconception is that head lice can jump or fly from one person to another. Head lice only crawl, most often leading to transmission through direct head-to-head contact.
Female head lice can lay up to 10 eggs a day. The eggs are usually found near the hair root, close to the scalp.
Researchers are unsure where lice originated, but they know that lice have affected primates for at least 25 million years, eventually spreading to humans. Head lice only affect humans, and they will not jump onto pets or other animals. Lice can also travel on objects that have touched the head.
Left untreated, head lice can lead to secondary infections, which can be serious. Bacterial infections, such as impetigo, can occur when scratched bites become infected; this can have serious consequences if not treated properly.
Vacuuming: While a vacuum is a good tool for cleaning up the ground after manual lice removal with a comb, it is not a wise idea to attempt to vacuum lice out of someone's hair. This is an uncomfortable and ineffective solution as lice have special claws to hold onto hair.
Exposing lice and nits to temperatures above 125 degrees F for 10 minutes is lethal. Most personal articles of clothing and bedding can be disinfested by machine washing in hot water or machine drying for at least 20 minutes using the hot cycle.
Lice are most commonly found at the back of your head and neck, and near your ears. If you think your child might have lice but you can't confirm it, ask their healthcare provider or school nurse for help.
Use fingers to separate hair and create a part. The part should allow you to clearly see the person's scalp. Look for lice crawling on the scalp where the hair is parted or on the hair shaft. The lice will be dark in color and the size of a poppyseed.
If you see nits and small moving lice, you've likely had lice for 1.5 to 2 weeks. This is because you aren't seeing a lot of adult lice but are still seeing tiny freshly hatched nymphs. If you find generations of head lice, meaning different sizes including nits, nymphs, and adult lice: 2 weeks or longer.
To confirm a case of head lice, you need to find live lice. Children can have a few nits without actually having a case of head lice. Usually children have no more than 10 to 20 live lice. Good lighting is important when you are checking.
If using Nix or Rid, it is recommended that you shampoo with the lice shampoo again on the 9th day after the initial shampoo. This step may not be necessary for Sklice. If you continue to see live bugs 2 days after shampooing, please call our office for recommendations.