CBS Local — Halloween is usually filled with creepy crawlers, but health experts are warning that there may be real ones lurking inside your costume’s mask this year.

Medical officials are sounding the alarm that head lice may become a disgusting nuisance for many children and adults who are trying on Halloween costumes. According to reports, doctors see a spike in head lice cases this time of year. While many blame the start of a new school year, the biggest culprit is actually Halloween costume shopping. The conclusion becomes even more ghoulish when you think of how many people may have tried on your mask or wig in the store before you bought it.

“We have a lot of people going into stores right now, trying on masks, trying on costumes and trying on wigs. And a lot of people don’t give much thought into the fact that several people could’ve tried it on before them,” Pediatric Nurse Practitioner Cherie Sexton told CBS affiliate WTOL. Sexton added that the risk of infestation can last for up to seven days after coming into contact with someone or something carrying lice.

Health officials have a few tips to make sure the Halloween horror doesn’t include head lice. Before wearing your costume or wig, putting it into a sealed plastic bag for 48 hours will kill any lice, which die within 24-48 hours. Putting any dryer-friendly costumes in the dryer on high heat for 45 minutes will also get rid of the critters.

Experts add that wearing a swim cap to cover your hair will create another barrier between you and any potential lice. “It’s really not a health hazard. It’s not a sign of poor hygiene. And it’s not really spreading disease. It’s really just more of a nuisance,” Sexton added.