How do you explain to a little girl that she can't have pizza or birthday cakes, ask the parents of three-year-old Hannah Devane.
Hannah suffers from a condition called eosinophilic esophagitis that produces a severe allergic reaction that causes her white blood cells to attack her esophagus. This makes it impossible for her to eat.
"It's really heartbreaking." Hannah's mother Jessie Devane said.
Michael Devane, who is her father, said, "It's very difficult to tell her that she can't have a cupcake or a piece of chocolate.
There's no cure for Hannah's condition, which affects one out of 10,000 children. She has suffered from this condition since she was 11 months old and depended on a special formula called Elecare for basic nutrition. The only other foods the toddler can eat are rice and pears.
But the Devanes' health insurance company is refusing to cover the cost of Elecare because, as the company told ABC News in a statement today, it is a "food supplement."
That leaves Hannah's parents Michael and Jessie -- a police lieutenant and a registered nurse -- with a $1,200 monthly bill. Hannah's father has taken on a second job as a security guard on weekends, and the additional pay barely helps cover the expense.
To make matters worse, Hannah's 6-month-old sister has just started to show the same symptoms Hannah once had.
"Hannah needs [Elecare] to survive. And we feel that the health system should be helping us to pay to keep our daughter healthy and alive," Michael Devane said. "Her disorder is being handled by a physician. So if this is being prescribed by a physician, and a physician is telling us, 'This is what your daughter needs' -- then as far as I'm concerned, that's a medical necessity, and our insurance company should cover that."
Dr. Glenn Furuta, who specializes in treating children with Hannah's disease, says Elecare is a medical necessity.
"The use of specialized formula for treatment of anyone with an allergic intestinal disease is a primary treatment," Furuta said. "It's not a supplement."
Without the formula, Hannah will become undernourished.
Today, knowing that ABC News' camera was there, the company that makes Elecare called the Devanes to say that they are donating two months' supply.
But many other children with food allergies are not so lucky. Parents and doctors say insurance companies are too often reluctant to cover desperately-needed formulas like Elecare, and they hope this will change.