The life cycle of the
Head lice can't spread disease, but they can make your scalp itchy. Frequent itching could break the skin on your scalp, which could lead to infections.
Untreated head lice may degrade the scalp and affects it health and that of the hair. If the follicles become blocked, then hair loss may occur. It is hard to have well-conditioned hair if it is covered in head lice eggs, lice and bacteria.
Their full life cycle, from egg until death, lasts a maximum of 35 days. The eggs are called nits and hatch into small insect forms — called nymphs — which then grow into adult lice.
Head lice live only on your scalp or behind your ears and at the back of your neck. They can't live for very long anywhere else. But you can have other types of lice on your body, such as body lice or public lice. If you have itchy skin or think you've seen lice on your body, talk to a pharmacist or see your GP.
A preventative shampoo and spray can break the life cycle. A shampoo that kills lice before they can lay eggs is critical for closing the “bridge” from one head to another.
Adult lice can live up to 30 days on a person's head. To live, adult lice need to feed on blood several times daily. Without blood meals, the louse will die within 1 to 2 days off the host. Life cycle image and information courtesy of DPDx.
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. Head lice move fast and are hard to see.
Head lice should not be considered as a medical or public health hazard. Head lice are not known to spread disease. Head lice can be an annoyance because their presence may cause itching and loss of sleep.
Head lice need a human host to survive. If the hair is gone, so are head lice. While cutting a child's hair may seem like an extreme solution, it may be a viable course of action for some parents. If your child already gets short haircuts, it may make sense for you to deal with head lice by destroying their habitat.
Head lice sometimes go away on their own because there are not enough insects to maintain the infestation, or they may persist for an indefinite period without treatment. With proper treatment, the infestation usually goes away within about two weeks.
Adults are not immune to head lice. In fact, if you have any close contact with children or even parents of children you can be at risk of catching them if they have them. Lice transfer primarily through head to head contact, so you would have to get close to the other person.
Many people with head lice have no symptoms at all. It's impossible to diagnose head lice based on symptoms alone since the only symptom that matters is the presence of lice. However, experiencing the following symptoms suggests it is time to check the scalp: frequent unexplained itching of the head or scalp.
Washing, soaking, or drying items at a temperature greater than 130°F can kill both head lice and nits. Dry cleaning also kills head lice and nits. Only items that have been in contact with the head of the infested person in the 48 hours before treatment should be considered for cleaning.
Not everyone feels lice moving around on their scalp, but some people do. Dr. Garcia says that most of her patients say they “don't feel anything,” but others may get a creepy, tickling sensation as lice move around their head.
Can head lice live on pillows or sheets? Head lice cannot live for long on pillows or sheets. It is possible for a live louse that has come off a person's head to crawl onto another human host who also puts their head on the same pillows or sheets.
Spinosad 0.9% topical suspension;
Spinosad topical suspension, 0.9%, was approved by the FDA in 2011. Since it kills live lice as well as unhatched eggs, retreatment is usually not needed. Nit combing is not required. Spinosad topical suspension is approved for the treatment of children 6 months of age and older.
Nits may remain after lice have gone. They are empty eggshells and stick strongly to hair. They will eventually fall out. If you prefer, a fine-toothed 'nit comb' can remove them.
After mating, the adult female louse can produce five to six eggs per day for 30 days (8), each in a shell (a nit) that is 'glued' to the hair shaft near the scalp (5,6). The eggs hatch nine to 10 days later into nymphs that molt several times over the next nine to 15 days to become adult head lice (5).
Pillows? Just like with mattresses, lice can only live on any bedding—whether it's sheets, pillows, or comforters—for 1-2 days. Without a human scalp as a source for food (blood) for longer than 1-2 days, lice cannot survive.
Head lice have no wings and do not fly or jump, but they can crawl or run through hair quickly. Most commonly, head lice are spread by direct head-to-head contact with an infested person.
How many head lice are usually found on an infested person? Typically, 10–15 head lice are found. The number of lice often depends on personal hygiene, for example, how often the person bathes, shampoos, or changes and washes his/her clothing.