I have a favorite comparison: When we fight cancer, we use chemotherapy because the poison is better than the cancer. When we fight lice, using poison makes no sense because methods far less toxic can do the job even better. This week I treated a young client who was exposed to a pesticide called Malathion. Malathion is only available by prescription and requires an 8-12 hour treatment. It is marketed under the name “Ovide.” Here is some basic information about Ovide and some other head lice pesticide treatments currently available by prescription and over the counter.
The CDC acknowledges that Ovide may only be partially ovicidal. This means that it only kills some lice eggs (nits) but not all. Further, this means that an additional 8-12 hour exposure may be necessary to kill any remaining bugs that hatch from those nits left viable after the treatment. I find it curious that a doctor would prescribe this as a first line treatment, knowing that it isn’t guaranteed to be a one time treatment. Of course, I’m not a doctor and I am not privvy to all the factors that went into making that decision.
So, then there is Lindane. Lindane is no longer recommended by the American Academy of Pediatrics, however, according the FDA, nearly 1 million prescriptions are written annually for this pesticide. It can have serious neurological side effects if misused and it is not a guaranteed ovicide. Aerial use of Lindane on crops is no longer permitted. Additionally, the FDA lists the possibility that a second application of Lindane may result in some severe side effects including death. I’d rather take my chances with the lice, thank you.
Moving down the line, we find Ulesfia. Ulesfia is a benzyl alcohol lotion. It is an effective pediculocide (it kills lice) but it is not an ovicide (it does not kill nits/eggs). This means that unless the viable nits are removed from the hair, they will continue the cycle of infestation. So, one either must comb the nits out of the hair completely, OR retreat with Ulesfia. The instructions recommend another treatment in 7 days. As someone who knows that the life cycle of the nit involves a 7-10 day incubation period, I would vehemently argue that the treatment needs to be repeated after 10 days not 7. That said, benzyl alcohol is systemically absorbed and it is toxic. I’d also like to point out that many people who have been experiencing a lice infestation tend to scratch their scalp. For a moment, imagine what it will feel like to apply alcohol to an irritated scalp. Makes you squirm, right? If one is only killing live lice and not nits, the same end could be achieved with a non-toxic product. Weighing the options, I still don’t understand using something more toxic when there is a suitable non-toxic option available. But that’s just me.
Next on the hit parade, we have Natroba. Recently approved by the FDA, this is a combination of the pesticide Spinosad and benzyl alcohol. Natroba claims to kill nits and therefore does not require that parents comb the nits out of the child’s hair in order for the treatment to be effective, however, there is also a recommendation that if there is live activity after 7 days, the product must be reapplied. This means that they know it isn’t killing 100% of the eggs. How does Spinosad kill lice you ask? Well, according to the product information “Spinosad causes neuronal excitation in insects. After periods of hyperexcitation, lice become paralyzed and die.” So, translating, the lice shake uncontrollably until they become paralyzed and die. Nice. Can’t wait to pour that on my kid’s head.
Also, more recent is Sklice, a topical preparation of Ivermectin, a pesticide that has been used orally for ringworm and scabies for many years. According to product literature provided by the manufacturer, there is no conclusive data as to whether Ivermectin causes cancer and Sklice is effective “about 75% of the time” at ending lice infestations. Given that it might cause cancer, how eager are you to risk being in the 25% of people who treat with this product and still have lice?
Now, on to the over-the-counter stuff. Pyrethrins with piperonyl butoxide is marketed under the popular name “Rid.” This product has been in use for decades and while it was once very effective against lice and their eggs, it has become less and less effective. Additionally, people who are allergic to chrysanthemums and/or ragweed may be advised not to use this product. Like antibiotic resistant bacteria, the lice have evolved immunity to the pesticides that have been in use for so long. Routinely, I treat clients in my office who have used these over-the-counter pesticides and still have live bugs in their hair. And even when the pesticide is successful in eliminating live activity, we know that the nits remain viable and a source of continued infestation.
There is also Permethrin. Permethrin 1% is marketed commonly under the name “Nix.”As with pyrethrins with piperonyl butoxide, lice have evolved a resistance to this pesticide. We routinely see clients who have used this product and present with live activity and/or continued infestation due to the fact that the nits have remained viable and have continued to hatch. Some clever manufacturers are now marketing a permethrin spray for the home so that worried parents can kill lice around their homes and in their cars. How nice. Interesting though, that with a vacuum or an adhesive lint roller, one can remove live lice from the home and other environments. Why companies are encouraging parents to spray poison in their homes in an effort to “clean” the home, I cannot explain or understand. Frankly, I’m not embarrassed to admit that it angers me. It angers me that these manufacturers prey on vulnerable parents and that they are fueling the very panic that keeps parents from reporting lice when it occurs in their home.
So, to sum up, we have Malathion, Lindane, Benzyl Alcohol, Spinosad with Benzyl Alcohol, Pyrethrins with Piperonyl Butoxide and Permethrin. There are non-toxic methods for dealing with head lice that are even more effective, so why would one choose something caustic or toxic for treating this problem? Have questions about how to handle a lice problem in your home? Send me an email firstname.lastname@example.org.
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