Welcome to the age of selfie-transmitted diseases.
According to one expert, teens posing for group selfies have been getting in so close that they're giving each other head lice.
The infestation usually spreads when kids share towels, hats, or headphones, but selfie-obsessed teens are cutting out the middleman and rubbing their lice directly on each other's heads, said Mary McQuillan of California head lice treatment center Nitless Noggins.
"I've seen a huge increase of lice in teens this year. Typically it's younger children I treat, because they're at higher risk for head-to-head contact. But now, teens are sticking their heads together every day to take cell phone pictures," McQuillan told SFist.
"Selfies are fun, but the consequences are real."
But not every medical professional is convinced selfies are spreading anything other than a few unfortunate cases of duckface.
A medical resident told CNET that the head-to-head contact in a group photo probably doesn't last long enough to reliably transmit lice, and a professor at the Harvard School of Public Health also registered skepticism about the supposed outbreak.
"This is a marketing ploy, pure and simple," Dr. Richard J. Pollack told NBC News. "Wherever these louse salons open a new branch, there always seems to be an epidemic. It's good for business."