Often traditional treatments for head lice can fail. If they do, a person may wish to use prescription treatments or visit a dermatologist.

Having head lice can make a person’s scalp extremely itchy. If people scratch it a lot, it can cause sores to develop on the scalp, which may lead to an infection.

Head lice are common and approximately 6–12 million children between the ages of 3–12 years old get head lice in the United States each year.

People commonly treat head lice with over-the-counter (OTC) head lice shampoos, which do not require a prescription to purchase. In some cases, these treatments may fail to work effectively.

In this article, we discuss why traditional treatments for head lice often fail. We also outline the steps a person can take if their treatment fails and explain how to avoid contracting head lice.

young girl who may have head liceShare on Pinterest
Catherine Falls Commercial/Getty Images

Traditional head lice treatments come in the form of OTC nonprescription shampoos and cream rinses.

People have been using these treatments for years. During this time, the active ingredients have mostly remained the same.

New generations of head lice have become immune to these treatments over time. Medical professionals refer to this as “resistance”. This resistance means that these head lice products may fail to work. Resistance to these traditional treatments is increasing.

If a person uses traditional treatments for head lice and they fail, they should visit their healthcare professional, who will recommend the best line of treatment.

A medical professional may suggest one of the following options:

The Food and Drug Administration (FDA) has approved prescription head lice treatments for children as young as 6 months of age.

These prescription treatments can be more effective than standard treatments because they contain different active ingredients than OTC treatments.

One FDA-approved prescription drug for head lice is malathion lotion. This medication kills the live lice and sometimes kills the lice eggs (nits).

A person should always follow a medical professional’s instructions when using malathion lotion. They should also consult the instructions inside the package or on the label.

The Centers for Disease Control and Prevention (CDC) outlines the following steps for using malathion lotion:

  1. Apply the lotion to dry hair and thoroughly coat the scalp and hair, especially behind the ears and on the back of the neck.
  2. Leave the lotion on the hair for 8–12 hours and allow the hair to dry naturally. Do not use an electrical heat source to dry the hair.
  3. Once the person receiving treatment has applied the medication, they should change into clean clothing.
  4. After 8–12 hours, thoroughly shampoo the hair and clean it. Then use a fine-toothed nit comb to remove dead lice and nits from the hair.
  5. For 2–3 weeks after treatment, use a fine-toothed nit comb to check for live lice every 2–3 days.

The CDC adds that if live lice are still present 7–9 days after treatment, the person should treat their hair again with a second application of malathion lotion.

People should consider treating their hair with malathion lotion before they go to bed. They should cover any pillows with a towel to prevent staining.

If standard head lice therapies fail to work, a person should consider visiting a board certified dermatologist.

These doctors specialize in diagnosing and treating conditions affecting hair and the skin.

They can make a proper diagnosis and suggest an effective treatment. This may be one of the prescription treatments.

A dermatologist may also show the patient or caregiver the proper combing technique for removing head lice. The correct technique can be very effective as it can kill the lice and help remove the lice and the nits from a person’s hair.

Several possible natural remedies may help a person treat their head lice.

One 2016 study tested various natural oils for the treatment of head lice. The researchers placed each oil on filter paper and added it to Petri dishes that contained 15 female head lice and another with 10 nits.

The researchers compared the head lice mortality rate and the hatch rate of the nits for each natural oil. They also compared these oils with malathion.

The study concluded that the following oils were an effective treatment for head lice and had an insecticidal activity that was similar to malathion:

Research into the effect of natural home remedies on head lice is ongoing. More research needs to determine if these natural oils are more effective than OTC and prescription treatments.

There are several steps a person can take to prevent a head lice infestation. These include:

  • avoid head-to-head contact with other people
  • do not share the following clothing with other people:
    • hats
    • scarves
    • coats
    • sports uniforms
    • hair ribbons
    • barrettes
  • do not share combs, brushes, or towels with other people

Tips for a person who has come into contact

If a person has come into contact with a person with a head lice infestation, they can take the following steps to avoid an infestation:

  • do not lie on the following items that have been in recent contact with a person with a head lice infestation:
    • beds
    • couches
    • pillows
    • carpets
    • stuffed animals
  • machine wash and dry clothing, bed linens, and any other items that have come into contact with a person with a head lice infestation
  • vacuum the floor and furniture, particularly where a person with a head lice infestation has sat or laid down
  • disinfect any combs and brushes that a person with a head lice infestation has used by soaking them in hot water that is at least 130°F for 5–10 minutes

Head louse is a common infestation affecting millions of people in the U.S. yearly.

The standard treatment for head lice is OTC shampoos and lotions that contain active ingredients that kill the lice.

These active ingredients have often remained the same for long periods. As a result, newer species of head lice have developed resistance against them. This resistance can cause standard therapies for head lice to fail.

If this happens, a person should contact their doctor. A doctor could arrange for the person to see a dermatologist. They may also recommend prescription medications that can help treat the infestation.