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When Lice Becomes Deadly

Recent cases of lice and anemia have people wondering how these blood-sucking insects can kill.

By Bill Sullivan
Jun 5, 2021 5:00 PM
doctor examining child's head for lice - shutterstock 1252772110
(Credit: Andrey_Popov/Shutterstock)


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In April 2021, a 4-year old girl was near death when her grandmother rushed her to a hospital in Scottsburg, a small town in southern Indiana. The girl had lost so much blood that doctors had to administer four blood transfusions. The loss of blood was not due to an injury or bleeding disorder, but a most unusual suspect: lice.

It sounds impossible that lice, a rather common malady among children, can be deadly. But the story above is not an isolated incident. On August 26 2020, Katie Horton rushed her 12-year old daughter Kaitlyn to the hospital after she was found unresponsive at their home in Ivey, Georgia. Kaitlyn died later that day of heart failure, although it did not go unnoticed that she had a massive lice infestation that may have persisted for years. Doctors listed severe anemia, a deficiency of red blood cells, as the secondary cause of death, due to the blood-sucking lice parasitizing her. Consequently, Kaitlyn’s parents were charged with child cruelty and second-degree murder.

A smattering of additional case reports of anemia caused by lice can be found in medical journals. The winner for the most ominous title goes to doctors at Conquest Hospital in East Sussex, UK. Their 2014 report, “A ghost covered in lice: a case of severe blood loss with long-standing heavy pediculosis capitis [head lice] infestation,” describes severe anemia in an 11-year old boy who was pale, lethargic, lightheaded, and “covered in lice.” 

Not all of the cases involve children. Severe anemia associated with lice has been described in a 61-year male and a 23-year old woman. Cases of lice causing anemia in cattle have also been documented.

Nonetheless, it remains hard to fathom that something as small as a louse, which is less than 4 millimeters in length (about half the size of a grain of rice), could drain enough blood to cause health problems. These startling reports raise a real “head-scratcher” of a question: Is death by lice really plausible? 

How Much Blood Can a Louse Devour?

Aileen Chang, assistant professor of dermatology at University of California, San Francisco, states, “Chronic or heavy lice infestation has been associated with iron-deficiency anemia, believed to be caused by lice taking repeated blood meals over time, but large studies have not been performed.”

It can be difficult to definitively implicate lice as the cause of life-threatening anemia because of confounding variables. Menstruation, internal bleeding, or celiac disease can also cause anemia. Chang adds, “Having a medical condition such as serious mental illness causing neglect in self-care or having social risk factors like lack of access to hygiene services can increase the chances of having chronic or recurrent lice infestation.” Indeed, in many of the case reports, the children were neglected and lived in squalor.

Neglected children are also likely to be malnourished, which is another risk factor for anemia. Iron, for example, is required for the body to make the hemoglobin in red blood cells, which allows them to distribute oxygen to the body’s tissues and organs. A lack of iron in the diet can make a person anemic.

In 2006, physician Rick Speare at James Cook University in Australia led a study to quantify the amount of blood that a louse could intake. Speare weighed lice before and after a blood meal, calculating that an average lice infestation would drain the victim of a paltry 0.008 milliliters of blood per day (one teaspoon is approximately 5 milliliters). However, large and chronic infestations involving thousands of lice can add up to a loss of 20 milliliters of blood per month. Speare concluded that if victim is already iron-deficient due to disease or a poor diet, this additional loss of blood can lead to anemia.

Anemia arising from a lice infestation is exceedingly rare. The infestation has to be abnormally large and persistent, and is most likely accompanied by a pre-existing condition that has diminished iron levels. Rest assured that standard cases of lice are not going to develop into anemia. But that doesn’t make them any less annoying, so how can we banish these tiny vampires from our lair of hair? 

Getting Rid of Lice

It’s not unusual for a parent to receive a daunting message that their child’s head is crawling with tiny blood-sucking parasites. An estimated 6 to 12 million head lice infestations occur each year in the United States among children under 11 years of age. Outbreaks of head lice typically happen at daycare centers and schools when direct contact allows a louse to crawl from one person’s hair into another. Less commonly, head lice can be transferred through objects that have come in contact with an infested person’s hair, such as brushes, scarfs, or hairbands.

Most cases of head lice can be eradicated at home using an over-the-counter product formulated to kill the adult lice. Chang suggests applying permethrin 1 percent lotion or other pyrethrin-containing topical agents. She adds that “Resistance to pyrethrins is a concern in some communities; in that case, prescription topical medications including benzyl alcohol, spinosad, and ivermectin can be used.” The eggs (nits), which are glued tightly onto hair shafts, must be meticulously removed using a fine-tooth nit comb. The treatment should be repeated as directed until nits are no longer evident on the comb.

Head lice do not survive long on clothes, bedding, and surfaces, but these items can be washed as a precaution. In contrast, body lice live on clothing, not the skin. “Body lice infestation occurs because of poor hygiene and lack of clean clothes. Therefore, the treatment is to launder clothing in hot water and high heat or replace the affected clothing,” Chang says. Further treatment directions for all types of lice can be found at the Centers for Disease Control website.

What About Other Blood-Sucking Bugs?

People are vulnerable to other blood-sucking bugs, including ticks and bed bugs. When asked if other parasitic insects could cause dangerously low levels of blood, Chang replied, “Since the hypothesis is that repeated blood meals lead to anemia, other blood-sucking bugs could have a similar effect. Bed bugs were associated with anemia (though not severe anemia) in a recent study, and one case report has linked severe anemia with a heavy bed bug infestation.”

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