What kills lice eggs and nits?

Head lice are wingless insects that live and breed in human hair and feed on blood from the scalp. They are a common nuisance, especially among school children. Getting rid of head lice requires removing both the live lice and their eggs, known as nits. Nits are small, teardrop-shaped eggs that attach to the hair shaft. They are very small, about the size of a knot in thread. Nits can be tricky to remove because they cling so tightly to the hair shaft.

There are several methods for killing and removing lice eggs and nits from the hair:

Medicated shampoos and products

Over-the-counter medicated shampoos, creams, and lotions can help kill lice and eggs. Look for products containing ingredients like:

• Permethrin – This is a synthetic pyrethroid insecticide that kills live lice. It may require a second treatment about 7-10 days later to kill any newly hatched lice.
• Pyrethrins – Derived from chrysanthemum flowers, these compounds can kill live lice. As with permethrin, a second treatment is often needed.
• Benzyl alcohol – This can suffocate and kill lice.
• Dimethicone – A silicone-based fluid that coats and suffocates lice.
• Ivermectin – This oral medication causes paralysis and death of lice when they ingest blood from a treated person.

Always follow the product instructions carefully. Using too much or too frequent of doses can be unsafe. Medicated rinses can help remove dead lice and make combing easier, but not kill 100% of eggs.

Wet combing

Wet combing involves using a fine-toothed lice comb to manually remove lice, eggs, and nits after washing and conditioning the hair. This method essentially combs the bugs off the hair. Steps include:

1. Apply a generous amount of conditioner to wet hair. This stuns the lice and makes removal easier.
2. Use a fine-toothed lice comb to comb through the hair, dragging from the scalp to the ends.
4. Frequently wipe the conditioner off the comb onto a paper towel to dispose of any lice.
5. Comb through the entire head, section by section. This may take 30-60 minutes for long or thick hair.
6. Rinse out conditioner once done.
7. Soak comb in hot water between uses.
8. Wash hair as usual after.
9. Repeat combing every 2-3 days for at least 2 weeks until no live lice are spotted for 10 days.

Wet combing is very effective for mechanically removing nits and lice but does not kill the eggs. It must be repeated frequently and thoroughly over a period of time to catch newly hatched lice.

Vinegar

White vinegar can help make eggs more easy to remove. The acidity helps dissolve the “glue” holding the egg to the hair. To use vinegar:

1. Start with dry hair.
2. Spray or pour white vinegar liberally over the scalp and hair lengths.
3. Let sit for 15-30 minutes, then rinse out.
4. The vinegar smell will dissipate once dry.
5. Use a lice comb to gently remove eggs loosened by the vinegar.

Vinegar can make the eggs easier to mechanically remove with a lice comb. However, it does not kill the lice or eggs on its own. Use it in combination with combing.

Olive oil

Like vinegar, olive oil can help loosen nits and eggs from the hair shaft for easier removal by combing. Here’s how:

1. Coat dry hair well with olive oil.
2. Cover with a shower cap or towel and let sit for at least 30 minutes, up to overnight.
3. Shampoo and comb out the oil and loosened nits using a lice comb.
4. The oil does not kill lice but makes mechanical removal easier.

The oil helps smother the lice while the shower cap deprives them of air. This can reduce their activity but does not always kill them. Focus on combing out the loosened nits after.

Mayonnaise

Like olive oil and vinegar, massaging mayonnaise into the hair and scalp can help loosen nits for easier removal. Mayonnaise is thick and sticky so it coats the hair well. Follow a similar method:

1. Rub a generous amount of mayonnaise into dry hair.
2. Cover hair and let sit for at least 30 minutes.
3. Shampoo and rinse out the mayonnaise.
4. Use a nit comb to remove loosened nits.

The mayonnaise helps smother and potentially weaken the lice. But its main utility is to loosen nits for easier removal by combing and washing.

Essential oils

Some research indicates that certain essential oils may have insecticidal effects and could potentially kill lice. However, most evidence is preliminary. Oils like:

• Tea tree oil
• Eucalyptus
• Lavender
• Thyme
• Ylang ylang
• Anise

Have shown some ability to kill head lice in vitro or through contact. However, evidence confirming efficacy in live human trials is limited. Using essential oils may help but should not be the sole treatment method.

Dimethicone-based oils

As noted above, dimethicone is a silicone-fluid used in some OTC head lice products. Oils containing dimethicone can essentially suffocate and immobilize lice through their coating action. Here’s how to use them:

1. Apply the dimethicone oil liberally to dry hair and scalp.
2. Leave on overnight with a shower cap.
3. Shampoo out the oil using regular shampoo.
4. Use a nit comb to help remove immobilized lice and nits.
5. May require repeat applications.

Dimethicone oils help suffocate and immobilize lice. But combing and repeat applications may still be needed to fully remove nits.

Nit-loosening combs

Specialty combs can help mechanically loosen and remove nits from hair strands. For example:

• LiceMeister – This battery-powered comb uses vibrations and teeth to dislodge nits.
• Robi Comb – Uses metal teeth that magnetically repel one another to grasp and remove nits.
• Terminator Combs – Have microgrooves on the teeth to better grasp slippery eggs.

These special combs can remove nits more efficiently than regular combs. But they do not kill active lice or unhatched eggs. Combing must be repeated thoroughly and often to catch new hatchlings.

Prescription treatments

For severe cases, doctors may prescribe:

• Higher-dose permethrin or pyrethrin rinses.
• Oral ivermectin tablets.
• Benzyl alcohol lotions – Kills lice by suffocation.
• Spinosad suspension – Made from soil bacteria metabolite that disrupts insect nervous systems.
• Malathion lotion – Organophosphate insecticide that kills lice.

These treatments are more potent and thus may be more effective than OTC options. But they still require repeat applications and thorough nit combing.

Hot air

Using a blow dryer on a hot setting may have some effect against lice and their eggs. Steps include:

1. Set blow dryer to highest heat setting.
2. Section dry hair.
3. Run the dryer over each section for 30 seconds, holding it about 6 inches from scalp.
4. Be careful not to burn the scalp.
5. May take several 30-second applications to comb through all hair.

The concentrated high heat can potentially desiccate and kill some lice. But results are variable. It should not be the only treatment method used.

Heated hair straighteners

Hair straightening irons or flat irons reach high heat levels which may have some effect on killing lice and eggs. To use them:

1. Set flat iron temperature to approx. 300°F – 350°F.
2. Work on small sections of dry hair at a time.
3. Run straightened plates along the hair length 2-3 times.
4. Take care not to actually press and straighten the hair.
5. Work through the entire head section by section.

The concentrated heat may kill some lice through desiccation. But results can be inconsistent. It should be combined with other removal methods.

Dryer sheets

Wiping the hair with dryer sheets like Bounce or Downy has been touted as a home remedy against head lice. But there is little evidence that dryer sheets alone can kill lice or their eggs. The sheets may help remove some live bugs through the coating action but are not a standalone treatment.

Conclusion

In summary, some of the most effective methods for killing and removing lice eggs and nits include:

• OTC or prescription medicated rinses, shampoos, lotions containing insecticides like permethrin or benzyl alcohol.
• Wet combing using a fine-toothed metal lice comb to mechanically remove nits and lice from the hair shaft.
• Loosening agents like vinegar, mayonnaise or oil to loosen sticky nits for easier combing removal.
• Manual nit-removal combs designed to efficiently grasp and pull out nits.

No single method can kill or remove 100% of lice and nits alone. A combination of chemical and mechanical removal techniques repeated thoroughly over 10-14 days is required to fully break the lice life cycle. Consistent combing and re-treatment is key for success. With perseverance, it is possible to get rid of lice, nits and eggs and prevent reinfestation.