Of all the possible infestations of children the two that cause the most disgust and anguish seem to be pinworms and lice. Neither are associated with significant consequences but there will be few readers who will not start scratching while reading. The earliest known evidence of pinworms was found in Utah of pinworm eggs carbon dated to 7837 BC. Lice have been around a very long time with genetic studies showing humans and lice having a relationship over 1.68 million years. The oldest physical evidence is a lice nit found on the hair of a 10,000-year-old body.
Intact nits have been discovered on the heads of mummies and their treatment has been a problem from Aristotle to Louis Pasteur. The war on head lice has been going on for thousands of years. A recent article in the journal Pediatrics, Dr. Dawn Nolt et al, reported on the current ways of diagnosing infestation and treatments.
Head lice are about the size of a sesame seed. Lice do not hop or jump; they can only crawl. They can attach to anybody’s hair, short or long, clean or dirty, straight or curly. They do feed on small amounts of blood from the scalp. They inject a small amount of their saliva causing the scalp blood vessels to dilate and prevent the blood from clotting. When the infected person becomes sensitized to the saliva they start itching. This may take 4-6 weeks in the first infection so the infected person may not know they have a problem.
To check for head lice put your child in a brightly lit room, part the hair, look for crawling lice one section at a time. Lice can crawl quickly and a typically affected scalp may only have 10 live lice. Lice eggs, called nits, are small white or yellow-brown specks and are firmly attached to the hair shaft near the scalp. Nits can easily be confused with dandruff, dirt particles or hairspray droplets. It is helpful to use a fine-tooth comb and look at the posterior hairline.
Live nits are found on the hair shaft very close to the scalp. If nits are found more than a half inch from the scalp, they are unlikely to be alive. Nits, dead or alive, are firmly attached to the hair shaft. If lice are found check with your health care provider before any treatment. The most effective way to treat is with head lice medicine but should be used only when living head lice are found. After each treatment remove nits every 2-3 days for 2-3 weeks.
You might want to wash your child’s clothes, towels, hats and bedlinens in hot water and dry on high heat if they were used 2-3 days before lice being found. One study found only 4% of possibly infected pillowcases had live lice. All household members and close contacts should be checked for lice. Do not spray pesticides in your home.
Schools should not keep children who have nits out of school.
by Sally Robinson, MD Clinical Professor
Keeping Kids Healthy
Published 10/2022
Also See: UTMB Pediatrics - Pediatric Primary Care