Yale Pediatrician's Newly Invented Head Lice Shampoo Sheds Light on an Age-old Problem Facing Children and Parents

To combat the prevalent problem of head lice in children, a Yale pediatrician has invented a shampoo that makes the nits visible under ultraviolet lights, making for easier, more effective removal.

The shampoo contains a non-toxic fluorescent dye that binds to the outer shells of the nits, or eggs, which are largely made up of chitin, a strong, flexible, light material. The dye causes the nits to glow brightly on the hairshaft when viewed under ultraviolet light. Sydney Spiesel, M.D., assistant clinical professor of pediatrics at Yale School of Medicine, invented the shampoo after dealing with an epidemic of head lice at a New Haven day care center.

As the medical advisor to the day care center, Spiesel was charged with the task of examining the children and certifying them bug-free. “Unfortunately, many of them weren’t free of nits and I learned what a really difficult job clearing a head is,” Spiesel said. “The nits are tightly cemented to the hairs, are tiny – about the size of a grain of sand – and are devilishly hard to see, especially in thick hair.”

Spiesel found that it took a minimum of 45 minutes to clear a head – a job that has to be repeated to be effective. He said lice have evolved to become more resistant to virtually all of the old chemical pediculocide-based treatments.

Even though lice carry no diseases and cause no real harm except an itchy scalp, Spiesel said there is still a lot of shame and embarrassment attached to a lice infestation.

“People associate lice with poverty and poor hygiene, probably because in the past, the problem was found among poor people living closely together with little opportunity to bathe and shampoo with hot water,” Spiesel said. “These days, head lice seem to especially favor wealthier people, but old prejudices are hard to break down.”

Lice are passed from head to head, usually by direct contact. Spiesel said they don’t fly or hop and their eggs are tightly bound to the host’s hair. The transfer often occurs when two children are playing or napping close together and the louse simply walks from one head to another. The bugs survive for about a day away from their host’s head, but they can also be passed by shared combs, brushes, hats or pillows.

Spiesel said the shampoo isn’t really a treatment, but a disclosing agent that helps parents find nits and lice so they can be easily and thoroughly removed. Current treatments include pediculocide shampoos and rinses which are intended to poison the bugs or the nits.

“These no longer work, at least on nits, because they have developed resistance,” Spiesel said. “Many parents now resort to drowning the bugs – for instance oiling the scalp with olive oil or mayonnaise overnight under a shower cap, and handpicking the nits to break the cycle of reinfection as the eggs hatch. Because of the high probability of missing some nits, this process has to be repeated several times.”

Spiesel said his shampoo, which is completely non-toxic, doesn’t kill the eggs at all, it just makes them easy to see to simplify removal. Only ultraviolet or “black light” will cause the stained nits to glow. Sunlight, incandescent light, even candles have been used for centuries to help see nits so they can be picked out by hand or combed out, but the stained nits don’t look any different with these lights than unstained nits and aren’t any easier to see or remove.