YORK, Pa. -- After more than a year of wondering what was making their baby sick, a Pennsylvania couple finally got their answer. It's a diagnosis that changed their life, and they want other parents to know about it.

Slideshow: Toddler Allergic To Most Foods

Jackson Sharp is a happy toddler now, but that's after a year of being terribly sick. He had stopped eating and was losing weight.

"It really turned our life upside-down," Jackson's mother, Laura Sharp, said.

In September, Jackson's parents found out what was wrong.

"He's been diagnosed with eosinophilic esophagitis," said Sharp.

The condition is also called EE. It means that Jackson's allergic to almost every food you could think of.

"He's allergic to beef, turkey, chicken, pork, lamb, dairy, eggs," said Sharp.

"It's such a difficult situation; my heart aches for this family and for this child," said Dr. Michelle Klinec, an allergist who saw Jackson early on in his illness.

Klinec said EE affects 1 in 10,000 kids. The illness happens when there's a buildup of allergy cells in the esophagus.

"When you have that building of allergy cells, it causes injury and produces symptoms," said Klinec.

In Jackson's case, his esophagus swells and he has trouble swallowing. Sharp said the family has been forced to make big changes.

"When you childproof your house you think electrical outlets. You don't always think of food. That's our No. 1 priority here," she said. "There are times when he cries because he'll want the food we're having."

The family even had to change their laundry detergent because it contains soy.

Jackson can only eat a few fruits and vegetables. So his parents fill the rest of his diet with a specialized formula, but it's costly -- $700 a month. The family's insurance company will pay for the formula until May. After that it's uncertain.

Jackson faces the possibility of someday being on a feeding tube. But his mom isn't thinking that far ahead. She's hoping for other things.

"That he's able to run and play in the back yard just like any other child," Sharp said.

Klinec said EE is still an evolving diagnosis and they don't know what triggers it.