Does Nix Kill Lice Eggs? Understanding its Effectiveness Against Nits
Nix, containing permethrin, kills live lice but is not reliably ovicidal. While it can kill some newly hatched lice, a second treatment is crucial to eliminate any remaining nits that hatch after the initial application.
Understanding Head Lice and Nits
Head lice are tiny, wingless insects that live on the human scalp and feed on blood. Pediculus humanus capitis is the scientific name for these unwelcome guests. While not dangerous, they are incredibly itchy and highly contagious, particularly among children.
Nits, or lice eggs, are small, oval-shaped and firmly attached to hair shafts, close to the scalp. They appear as tiny yellowish-white or brownish specks. Nits are often confused with dandruff or hairspray residue, but unlike dandruff, they cannot be easily brushed off. A nit that has already hatched will appear clear or translucent.
The life cycle of a louse is approximately 30 days. A female louse lays about 6-8 eggs per day. These eggs hatch in approximately 7-10 days. Newly hatched lice, called nymphs, must feed immediately to survive. They mature into adult lice in about 9-12 days.
How Nix Works: The Active Ingredient
Nix is an over-the-counter (OTC) medication used to treat head lice infestations. Its active ingredient is permethrin, a synthetic pyrethroid insecticide. Permethrin works by paralyzing the nervous system of lice, leading to their death. It’s generally considered safe for use in children 2 months and older, but it’s essential to follow the instructions carefully.
Permethrin is effective against adult lice and nymphs, but its effectiveness against nits is less consistent. This is because the hard, protective shell of the nit makes it difficult for the permethrin to penetrate and kill the developing louse inside.
Nix Application: Step-by-Step Guide
To ensure Nix is as effective as possible, follow these steps carefully:
- Wash hair: Use a shampoo without conditioner.
- Towel dry: Remove excess water but leave hair slightly damp.
- Apply Nix: Saturate the hair and scalp with Nix, starting at the scalp and working outwards.
- Leave on for 10 minutes: Set a timer to ensure adequate contact time. Do not exceed the recommended time.
- Rinse thoroughly: Rinse with warm water.
- Comb through: Use a fine-toothed comb to remove dead lice and nits. This is tedious but crucial for complete removal.
- Repeat treatment: A second treatment is essential 7-10 days after the first to kill any newly hatched lice from nits that survived the initial treatment.
The Importance of a Second Treatment
The key to successfully eradicating head lice with Nix is the second treatment. Because permethrin isn’t reliably ovicidal, some nits may survive the first application. These nits will hatch a few days later, releasing new nymphs.
The second treatment, administered approximately 7-10 days after the first, targets these newly hatched nymphs before they mature and begin laying eggs themselves. This breaks the life cycle of the lice and prevents re-infestation.
Limitations of Nix and Potential Resistance
While Nix is a widely used and generally effective treatment, it does have limitations. One significant concern is the increasing resistance of lice to permethrin in some regions. This means that Nix may not be as effective as it once was, and alternative treatments may be necessary.
Factors contributing to resistance include:
- Overuse of permethrin: Frequent use of Nix can select for lice that are resistant to the insecticide.
- Improper application: Not following the instructions carefully can lead to ineffective treatment and contribute to resistance.
- Geographic variation: Resistance levels vary by region, with some areas experiencing higher rates than others.
Alternative Treatments
If Nix is ineffective, or if concerns about permethrin resistance exist, several alternative treatments are available. These include:
- Prescription medications: Malathion, spinosad, and ivermectin are prescription medications that are often effective against resistant lice.
- Dimethicone: This silicone-based product coats the lice and suffocates them.
- Benzyl alcohol lotion: This lotion paralyzes the lice, making them unable to feed.
- Manual removal: While time-consuming, meticulously combing through the hair to remove lice and nits can be an effective method, especially when combined with other treatments.
Common Mistakes When Using Nix
Several common mistakes can reduce the effectiveness of Nix:
- Not using enough product: Ensuring the hair and scalp are thoroughly saturated is crucial.
- Rinsing too soon: Leaving the product on for the full 10 minutes is essential for optimal results.
- Not repeating the treatment: The second treatment is vital to kill newly hatched lice.
- Using conditioner before application: Conditioner can create a barrier that prevents the permethrin from reaching the lice.
- Not combing through the hair: Combing helps remove dead lice and nits.
- Treating only the affected person: All members of the household should be checked for lice, and treated if necessary.
Frequently Asked Questions (FAQs) About Nix and Lice Eggs
Does Nix kill nits on contact?
No, Nix is not reliably ovicidal, meaning it doesn’t consistently kill nits on contact. While it may kill some newly hatched lice, many nits will survive the initial application. This is why a second treatment is necessary.
How long does Nix take to kill lice eggs?
Since Nix doesn’t directly kill lice eggs, the question of how long it takes is irrelevant. The second application, done 7-10 days after the first, is designed to kill the nymphs that hatch from the eggs that survived the initial Nix treatment.
What are the signs that Nix is working?
Signs that Nix is working include a reduction in itching, fewer live lice observed after combing, and a decrease in the number of new bites or sores on the scalp. However, it’s important to remember that the complete elimination of lice requires a second treatment and meticulous combing.
Is it safe to use Nix on children?
Nix is generally considered safe for use in children 2 months and older. However, it’s always best to consult with a pediatrician or pharmacist before using any medication on a child. Follow the instructions carefully and avoid getting the product in the child’s eyes, mouth, or nose.
Can I use Nix on my eyebrows or eyelashes?
No, Nix is not intended for use on eyebrows or eyelashes. These areas are too close to the eyes and the product could cause irritation or damage. Consult a doctor for safe alternative treatments for lice in these areas.
What should I do if Nix doesn’t work?
If Nix doesn’t seem to be working, consider the possibility of permethrin resistance. Consult with a doctor or pharmacist about alternative treatments, such as prescription medications or other OTC options. Also, ensure you are following the application instructions correctly and performing a second treatment.
How often can I use Nix?
Nix should only be used as directed, which typically involves two applications spaced 7-10 days apart. Using it more frequently can increase the risk of side effects and contribute to permethrin resistance.
Can I get lice again after using Nix?
Yes, it is possible to get lice again after using Nix, especially if you are exposed to someone who has lice. To prevent re-infestation, avoid close contact with infected individuals and practice good hygiene.
Does Nix expire?
Yes, Nix has an expiration date. Check the packaging for the expiration date and do not use the product if it has expired. Expired medications may be less effective or even harmful.
Does Nix kill scabies mites?
Nix is primarily designed to treat head lice. While permethrin is also used to treat scabies, the concentration and formulation may differ. Consult with a doctor to determine the appropriate treatment for scabies.
How should I clean my home after treating lice with Nix?
While lice cannot survive long away from a human host, it’s recommended to wash bedding, clothing, and towels used in the 2 days prior to treatment in hot water and dry them on high heat. Vacuum carpets and furniture, and consider bagging non-washable items for 2 weeks.
Are there any side effects of using Nix?
Common side effects of using Nix include itching, burning, stinging, or tingling on the scalp. These side effects are usually mild and temporary. If you experience severe irritation or an allergic reaction, discontinue use and consult a doctor.