Head lice are tiny wingless insects that feed on human blood. About the size of sesame seeds they have six legs with claws that they use to cling on to human hair and specialized mouth parts to pierce the skin and suck the blood. Contrary to what many people think lice can’t hop jump or fly but can crawl very speedily through the hair. They lay their eggs (nits) on the hair shaft using special “glue” that attaches the nits firmly to the hair.

Head lice are closely related to body lice which can live anywhere on the body. In fact they’re so similar in appearance that it’s very hard to tell them apart. Body lice however are known to spread infection whereas most doctors say that head lice are not dangerous. Still for anyone who gets infested head lice can be pretty unpleasant. Lice makes us scratch our hair because they use a chemical to stop the blood from clotting so they can keep sucking. Most people are sensitive to that chemical although some people aren’t — which is why they don’t scratch their hair even if it’s full of lice!