How to make the difference
Lice and dandruff are both uncomfortable conditions that cause itchy scalp and are easily mistaken for each other. While lice are a temporary infestation, dandruff is a chronic skin condition.
Head lice, also called pediculus humanus capitis, are parasitic insects that live and lay eggs on the scalp. They drink human blood, and their bites are very itchy.
According to the Centers for Disease Control and Prevention (CDC), there are six to 12 million cases of head lice each year in the United States. Young children are most at risk because they frequently have hair-to-hair contact with others at daycare or school.
Dandruff, also known as seborrheic dermatitis, causes small pieces of dry skin on the scalp to flake off. When seborrheic dermatitis occurs on the scalp of an infant, it is known as cradle cap.
While lice are very contagious, dandruff is not. Fortunately, both conditions can be treated safely and effectively at home.
Signs and symptoms
Although lice and dandruff can cause an itchy scalp, their symptoms are different.
The classic symptom of lice is intense itching. Bites from an adult louse cause an allergic reaction that is itchy. You may even feel a sensation of crawling. Young children may describe this sensation as a tickle in their hair.
Toddlers can also have trouble sleeping when they have lice, as head lice are more active at night. The scalp may also appear red and bleed from frequent scratching.
Lice and dandruff may look the same at first glance, but they occur in different places. Lice lay their eggs (called nits) on the hair shaft itself. Nits adhere to your hair and don’t flake like dandruff does. Nits are usually white or yellow and teardrop shaped.
Adult lice are tan, brown or black and can be seen with a magnifying glass. An adult louse is about the size of a sesame seed. They are usually found in the scalp and hair around the ears and the neckline.
Like lice, dandruff can be itchy, but it’s usually not as intense as the itchiness caused by lice. The drier the scalp, the more itchy dandruff usually causes. When you have dandruff, your scalp is usually very oily or very dry. You may notice that the symptoms worsen during the colder months due to the dry air.
Dandruff affects the scalp, not the hair itself. Looking closely, you will see white or yellow flakes coming from the scalp; these flakes then fall easily.
Seborrheic dermatitis can also affect other areas of the body, but is most often found on the scalp. While the lice will appear black or brown, the dandruff will appear white or yellow.
Lice are caused by an infestation of parasitic insects, while dandruff is caused by a yeast that grows on everyone’s skin called malassezia and inflammation.
Lice are very contagious. If you come into close contact with someone with lice, such as hugging, lice can easily crawl from their head to yours. Lice cannot jump or fly. Sharing hats or hairbrushes is another way to get infected with lice, but face-to-face contact is the most common.
Lice are more common in young children and those who work with them. High-risk occupations include teachers, educators and babysitters.
Seborrheic dermatitis is a chronic disease that causes skin cells in the scalp to shed too quickly, resulting in dry, itchy flakes that break off from hair and clothing.
Dandruff is a chronic skin condition that causes dry, scaly skin. You cannot get dandruff from another person. Lice, on the other hand, are very contagious parasites. Young children are particularly at risk of spreading lice between them.
Most cases of lice and dandruff can be successfully treated at home.
Lice can usually be treated at home with an over-the-counter medicated shampoo according to the directions on the package. It is also important to comb the nits of the hair carefully. Nits are usually found within a quarter of an inch of the scalp. Nits found further down the hair shaft are usually not viable and will not turn into lice.
If you are treating your child’s lice, call your pediatrician first to discuss the right amount of shampoo and how often to use it. This is often based on their age and weight.
Some common home remedies for lice treatment involve coating the scalp with heavy, fatty foods like mayonnaise, olive oil, butter, or margarine to suffocate the lice. These treatments have not been proven to be effective and are not recommended.
Here are some other important things to do:
- Avoid using conditioner in the hair until it is completely free from lice and nits. The conditioner can act as a barrier that prevents the medicated shampoo from adhering and processing the hair shaft.
- Since lice need a human host to survive, wash any items that could transfer them to a new host. This includes clothing, bedding, stuffed animals, hats, and any other item that has come in contact with the person’s head. The CDC recommends washing all items in hot water over 130 degrees F to kill both lice and nits. Items should then be dried in the dryer on the hottest setting. Vacuum all areas where the person with lice has laid down, such as rugs and furniture. Any items that cannot be washed or vacuumed should be sealed in a plastic bag for two weeks.
If over-the-counter treatments haven’t worked, see your doctor. It is possible that lice are resistant to over-the-counter treatment and you may need a prescription medication. Your local health department may also be able to help.
It is not always possible to prevent lice, but you can reduce your chances of getting them by taking precautions. Discourage your children from having hair-to-hair contact when playing with their friends, and avoid sharing hairbrushes or hats.
Dandruff can also be treated at home with an over-the-counter shampoo. Start by shampooing twice a week with anti-dandruff shampoo. Keeping dandruff shampoos in contact with your hair for five to 10 minutes is most effective. Washing your hair more frequently in general also helps to get rid of dandruff.
Be careful with dandruff shampoos that contain tar, as they can make your scalp more sensitive to the sun. The tar can also discolor blonde or white hair after treatment.
If using an anti-dandruff shampoo does not provide relief, see your dermatologist. Sometimes dandruff is caused by a yeast infection that requires an antifungal to be treated.
Some autoimmune diseases such as psoriasis or eczema can appear as dandruff, but require more specialized treatment. Your dermatologist can help you determine the cause of your flakes, as well as the best way to treat them.
Frequently Asked Questions
What do lice look like compared to dandruff?
Lice are six-legged parasitic insects and are usually tan, brown, or black. Their eggs look like teardrop-shaped eggs that are white or yellow in color. They are found attached to the hair shaft near the scalp.
Dandruff looks like white or yellow flakes of dry skin. It is generally larger than lice and their eggs and can appear oily.
How to check for lice versus dandruff?
To check for lice and dandruff, start by parting the hair and examining the scalp. When you have dandruff, your scalp appears either very oily or very dry. The flakes will come from the scalp and come off easily.
Lice lay their eggs on the hair shaft about a quarter of an inch from the scalp. The eggs are firmly attached to the hair and cannot be removed. Adult lice live on the scalp and usually appear tan, brown, or black. Sometimes a magnifying glass is helpful in identifying adult lice on the scalp.
How big is dandruff compared to lice?
Both dandruff and lice are extremely small and it can be difficult to tell them apart. An adult louse is about the size of a sesame seed, and its eggs are even smaller. Dandruff flakes are larger than lice and often appear and feel greasy.
How do you know if it is lice or dandruff?
Location is one of the best ways to tell lice from dandruff. Dandruff describes dry flaking skin on the scalp. Lice eggs, on the other hand, adhere to the hair shaft itself. Using a magnifying glass, you may be able to see adult lice moving on the scalp. This is difficult because they are usually only active in the dark.
Another symptom to watch out for is itching. Lice bites cause intense itching, while dandruff itch is more like dry, uncomfortable skin.
A word from Verywell
If you’ve found yourself scratching your head lately, take a closer look. Dandruff will appear as white or yellow flakes of dry skin. Lice eggs, also called nits, look like tiny yellow or white teardrop-shaped eggs. Adult lice are darker in color and the size of a sesame seed.
While both conditions can make your skin crawl, they are usually treated effectively at home. Invest in a medicated shampoo and talk to your doctor before treating young children.
If home treatments haven’t worked, call your doctor. They will be able to diagnose your condition and recommend the safest and most effective treatment.