Head lice infestations are a common concern, but a newer challenge has emerged: “super lice.” These are not a new species of lice but rather a strain that has developed genetic resistance to the active ingredients in many common over-the-counter (OTC) lice treatments. This resistance renders traditional chemical shampoos less effective, making eradication more difficult for many families.
Understanding Super Lice
Super lice are head lice that have acquired genetic mutations, allowing them to survive exposure to pyrethroid-based pesticides like permethrin and pyrethrin, commonly found in many OTC lice products. These mutations, often called “knock-down resistance” (kdr) mutations, alter the lice’s nervous system, preventing pesticides from effectively paralyzing and killing them. The widespread and sometimes incorrect use of these chemical treatments over decades has inadvertently selected for these resistant lice, allowing them to proliferate.
Effective Treatment Approaches
Successfully eradicating super lice often requires a multi-pronged approach that combines manual removal with alternative treatments or prescription medications. Manual removal, particularly wet-combing, is a fundamental step. This method involves saturating the hair with conditioner or a lice-specific lubricant, which immobilizes the lice and makes it easier to comb them out with a fine-toothed nit comb. The hair should be divided into small sections, meticulously combing from the scalp to the end of the hair shaft, and cleaning the comb after each pass to remove lice and nits. This process should be repeated every three to four days for at least two weeks, or until no live lice or nits are found for several consecutive combings.
Non-pesticide treatments offer another option, working through physical means rather than chemical ones. These products often contain ingredients like dimethicone or mineral oils that coat the lice, leading to suffocation or dehydration. Some heat-based devices specifically designed for lice treatment use controlled heated air to dehydrate and kill both lice and their eggs. These methods are effective as lice cannot develop resistance to physical actions.
For persistent infestations or when OTC options fail, prescription medications may be necessary. These treatments utilize different active ingredients that are not pyrethroid-based. These include spinosad, ivermectin, or malathion, which work through different mechanisms to kill lice. These medications require a doctor’s prescription and should be used strictly according to their instructions.
Beyond treating the infested individual, environmental cleanup plays a supportive role in preventing reinfestation. While lice cannot survive long off a human host, typically less than 24 hours, washing bedding, clothing, and recently used hats or scarves in hot water and drying them on high heat can help eliminate any stray lice or nits. Vacuuming carpets, upholstered furniture, and car seats can also remove any lice that may have fallen off. Sealing non-washable items in plastic bags for two weeks can also isolate and kill any remaining lice by depriving them of a food source.
Preventing Reinfestation
After successfully treating a super lice infestation, implementing preventive measures helps minimize the risk of reinfestation. Regular head checks are an important ongoing practice, especially for children who are frequently in close contact with others. These checks should be performed weekly using a bright light and a fine-toothed comb to detect any new lice or nits early, before an infestation can spread.
Limiting head-to-head contact, particularly during play or group activities, can significantly reduce transmission. Discouraging the sharing of personal items that come into contact with hair, such as hats, combs, brushes, hair accessories, and headphones, helps prevent lice from transferring between individuals.