Topicals: Head Lice


Head lice are very small, wingless, parasitic insects that live close to the human scalp and feed on blood. They are found primarily on the head, sometimes including the eyebrows and eyelashes. An adult louse is about the size of a sesame seed and can sometimes be difficult to spot. The eggs, called nits, are even smaller. According to the Centers for Disease Control and Prevention (CDC), head lice annually affect an estimated 6 to 12 million children between the ages of 3 and 11 years, but can affect individuals of other ages as well. Outbreaks typically peak after the opening of school during August and November. The CDC and the American Academy of Pediatrics report that head lice are not a health hazard and, contrary to popular myth, are not a sign of poor hygiene.

Signs and Symptoms

The most common symptom associated with head lice is severe itching on the head, behind the ears, or at the nape of the neck. Head lice symptoms may include:

  • Severe itching of the scalp
  • Red, irritated scalp
  • Tickling sensation that something is moving in the hair
  • Appearance of tiny white specks (the eggs or nits of the lice) on the hair shaft that are not easily removed
  • Small red bumps on the scalp, neck, and shoulders, and behind the ears


Head lice can appear in 3 different forms: eggs (nits), nymphs, or adult lice. Head lice move by crawling and cannot fly or jump. Head lice can be transmitted via direct contact with an infested individual or through indirect contact with a contaminated object such as a comb, hairbrush, hat, pillow, clothing, or towels.

Tests and Diagnosis

A diagnosis of head lice is best confirmed by observing active lice on the scalp, hair, and/or clothing of the infested individual. They are very tiny and move quickly, so a magnifying glass may be needed to find them. To check for lice, examine hair under bright, natural light by parting sections of the hair and examining each section closely. Look for small white, tan, or yellowish brown specks that are attached to the hair shaft near the scalp. When in doubt, always see your doctor to confirm that head lice are present so that treatment can begin as soon as possible.


Lice can live for approximately 30 days on the human head or about 24 hours off the scalp. To prevent the transmission of head lice or to avoid possible reinfestation, you should:

  • Avoid sharing items such as combs, brushes, hats, helmets, and towels
  • Adequately sanitize personal items by washing brushes, combs, hats, and toys with very hot water (≥) for at least 10 minutes
  • Launder all linens in hot soapy water (≥), and dry them on the hottest dryer setting, if possible
  • Seal objects that cannot be washed in plastic bags for at least 2 weeks
  • Routinely vacuum carpets, rugs, mattresses, and upholstered furniture

Treatment and Care

Treatment should begin as soon as lice are discovered. There are several OTC creams, lotions, and shampoos, known as pediculicides, for the treatment of head lice. These medications work by suffocating or paralyzing the head lice. Treatment is recommended for those with active head lice infestation. The American Academy of Pediatrics recommends 1% permethrin lotion as the initial treatment for most infestations of head lice, with a second application 7 to 10 days after the first treatment if active nits are still detected. It is important to adhere to the directions for the selected treatment and to adhere to treatment to ensure that the lice are completely eliminated. It is imperative that eggs and nits be carefully combed out of hair with a special fine-toothed comb during treatment. These combs are usually packaged with the medication. If these products do not appear to work, your doctor may prescribe a stronger medication.


If someone in your house has head lice, it is important to check everyone in the house for lice and treat those with active head lice. With proper treatment, lice can be easily eliminated. It is important to adhere to the recommended treatment directions and manufacturer’s warnings. If crawling lice are still observed after a full course of therapy, you should contact your doctor or pharmacist for recommendations regarding other possible treatments.Always contact your primary health care provider if you have any concerns or if you experience any adverse effects.

Resources for Patients

  • National Pediculosis Association
  • American Academy of Pediatrics

Resources for Pharmacists

  • Centers for Disease Control and Prevention
  • National Pediculosis Association

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