NBC NATIONAL NEWS — On a typical beach day, there are more than a few things you need to protect the kids.

"Everything possible," said mother Kiera Dunlap. "Towels. Definitely extra sunblock. Especially for your lips. A lot of people forget about that."

But Kiera Dunlap has never considered what could be happening inside her kids ears while they splash along the shore.

Bacteria could cause swimmer's ear.

That is an infection inside the ear channel that causes painful redness and swelling.

It's pain enough to turn the excitement of finding the perfect shell into a day of scrambling to find a doctor's office.

"I never had an issue with that," said Kiera.

Ear, nose and throat doctor, Dr. Vien Phommachanh, said it can happen to anyone just after one dip in the water.

"The moisture from swimming creates a warm environment in the ear and bacteria tends to accumulate and causes an infection," explained Phommachanh, Otolaryngologist.

He said it's more common in people who produce more than average ear wax or who have narrow ear channels like kids do.

It requires antibiotics to treat.

"And it can also cause complete blockage of the ear channel," added Phommachanh. "The ear cannel itself is like a tube and it can actually swell shut."

But don't jump out of the water for good.

There are steps you can take to prevent an  infection.

"There are solutions you can buy over the counter." Instructed Phommachanh. "Topically they contain vinegar."

But the doctor warns that these are not use to cure an infection that has already developed.

He said the best way to avoid the pain and swelling is pay close attention to the inside of your little swimmer's ear.

Nina Moini reporting.