While they might give you the creepy crawlies, head lice shouldn’t be cause for panic. Still, you’ll want to spot them early. Here’s how.

You got a warning letter from their school

Most schools and childcare centers will send a note home to parents as soon as a fellow student has been discovered with head lice. Don’t panic: Experts say lice are virtually harmless. They don’t carry disease or indicate poor housekeeping; they’re simply a parasite transmitted via head-to-head contact. Lice can’t jump, hop, or fly (though they can become projectiles through static electricity), and altering your child’s routine to avoid them is unnecessary. Instead, discourage your kid from sharing hair supplies and hats, and from touching heads with others.

They’re constantly scratching

One of the most obvious head lice symptoms is an itchy scalp. The tickling sensation is the result of an allergic reaction to louse saliva, and is most common around the top of the head, neck, and ears. Itching may not occur for two to six weeks after an infection. Children might also report feeling a moving sensation, which occurs as a result of the tiny insects crawling through their hair.

They’ve had trouble sleeping

This head lice symptom goes hand-in-hand with itchiness: Because lice are most active at night, children might experience more itchiness in the evening and have trouble falling asleep. If you notice your child twisting and turning at night, or acting irritable from a lack of sleep, you might want to check his or her scalp. 

They’ve got dandruff that just won’t let up

Lice eggs (or nits) can often take on the appearance of dandruff (and vice versa, so make sure you’ve diagnosed your child correctly by taking them to a professional before starting treatment). Nits are oval in shape and about the size of a knot in thread; they’re usually yellow or white in color and latch onto hair shafts about a quarter-inch from the scalp. So how can you tell them apart from dandruff, hair-product residue, dirt, and other harmless lookalikes? They won’t budge. “They can look just like a grain of sand, and they’re not easily removed from the hair,” Paradi Mirmirani, MD, a board-certified dermatologist, told Parents.

You see small red bumps on their neckline

Another one of the many head lice symptoms are any signs of irritation around the neck, scalp, ears, and shoulders. Red bumps in these areas can hint at intense scratching, which can occasionally lead to infection. 

They’ve got swollen lymph nodes

If broken skin from frequent scratching results in infection, you might notice the lymph nodes behind your child’s ears and on his or her neck become tender and swollen. Consult your doctor on this one. Your child might need a round of antibiotics.

You see physical evidence

Because lice are tiny (about the size of a sesame seed) and their eggs even tinier, physical evidence can be hard to spot. Pick up a lice comp (or a very fine-toothed comb) and wet your child’s hair. Slide the comb from scalp to end, checking its teeth after each swipe. A magnifying glass might be necessary. If you do find lice, don’t panic. Once you notice that your child has head lice symptoms contact your doctor, who will give you medication and treatment instructions.