Diagnosing Head Lice

I think my child has head lice. I keep my house clean, but I’m embarrassed and afraid other people will think it’s my fault. How can I check without going to the doctor?

Diagnosing Head Lice

Dr. Greene’s Answer:

Lice have been a nuisance to humans since ancient times. They have thrived almost wherever humans have been in prolonged close contact with each other. One notable exception to this has been in areas where the pesticide DDT is in widespread use. In the United States, for a period of about 30 years, lice outbreaks were uncommon. Since DDT was banned in 1973, the number of cases of lice has risen steadily. Today, there are about 12 million cases per year in the United States alone. Each year, many day care centers, schools, neighborhoods, extended families, and small family units face problems with lice. You are not alone.

Two myths:

Myth: Head lice restrict their activities to unclean houses, unclean heads, and unsavory sorts of folks.
Fact: Having head lice is not a sign of poverty or poor hygiene.

Myth: All heads of hair are equally attractive to lice.

Adult lice are six-legged, wingless insects 2-4 mm long. They have translucent grayish-white bodies, and look a bit like a grain of rice with six legs. Their heads have two tiny eyes (too small to be seen without magnification) and two small antennae (usually visible). Six pairs of hooks surround the mouth parts, by which they attach themselves to the skin of the scalp for feeding. The mouth contains two retractable, needle-like tubes that pierce the scalp. Salivary juices are injected into the scalp to prevent blood from clotting, and then the lice feed happily, sucking blood through these same tubes. Their translucent bodies turn reddish brown when engorged with blood. Lice completely depend on the blood extracted from humans for existence, and thus will starve to death after 55 hours without blood.



During this whole life cycle, larvae and adult lice deposit their feces in the scalp, which eventually causes itching as the person develops an allergic reaction to the lice stool. The hallmark symptom of head lice is itching, but a person may have lice for months before the itching begins. For me, just thinking about lice makes my head itch.

Now, a moment of silence to be grateful that lice can’t fly…



Frequently, people find “pseudo-nits” and panic unnecessarily. Bits of hair spray, dead skin scales, or loose debris may be seen on hair shafts. These move with pressure from the fingers — nits do not. Also, live nits glow when exposed to a black light (we use black lights in pediatric offices for inspection) and dead nits and empty nits do not.

Historically, the main method for getting rid of lice has been mechanical — physically removing the nits, or “nit picking,” such as apes do for each other during their daily grooming routine. About 30 years ago, powerful pesticides were introduced as lice treatments. For a time, they made treating lice much easier. Over the last several years, however, the lice have become increasingly resistant to these medicines. The resistance is growing. Now, once again, mechanical nit removal is the cornerstone of lice treatment, although the medicines can still be a real help.

Treatment for head lice can be effective, but it is not simple, easy, or inexpensive. A key to success is making sure that ALL individuals who may be potentially affected by the outbreak complete a radical eradication. If 99.99% of the lice are killed, but .01% are not, you already have the makings of another outbreak!

So, you can check easily for lice without going to the doctor, but you do not need to feel embarrassed or ashamed. Your doctor will understand and I do too — from personal experience.

Dr. Alan Greene


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