6-years-old boy allergic to almost everything EXCEPT Chick Fil-A fries

Many of us would love to have an excuse to eat Chick-fil-A all the time. 

But for little Christopher Cataldo, it is a bitter-sweet treat: he is allergic to almost every other food in the world.

The six-year-old, from Houston, Texas, has a rare and incurable condition called eosinophilic esophagitis (EoE), which means eating or even smelling most foods could kill him. 

After years of treating his food-triggered seizures, Christopher's doctors have concluded he can only eat nine foods: apples, grapes, plain rice, potatoes, tomatoes, lemons and bananas. 

Other foods aggravate his throat and colon, making him sick. He is also immune-compromised, meaning he cannot be in crowded places like a fast food restaurant. 

It means his mom Kellie has to check and prepare all of his food for him, and he can never spontaneously eat out like his friends and younger sister. 

However, scientists at Cincinatti Children's Hospital decided to test the potato fries on the Chick-fil-A menu to see if he could eat them.

A batch of Chick-fil-A's waffle potato fries are 400 calories.

They are made from potatoes cooked in vegetable oil.

According to the website, the other ingredients include disodium dihydrogen pyrophosphate (to promote color retention), fully refined high oleic canola oil, citric acid (to 'preserve freshness'), and Dimethylopolysiloxane (as an anti-foaming agent).

To the family's joy, the results came back clear: he can eat them.

Every day since the discovery, they have gone to get take-out fries from the drive-thru, because 'it makes him feel 'normal' in his words,' according to Kellie.

But he could never go in, because of the pathogen dangers of being in close proximity with so many people.  

And so, on Wednesday, their local Chick-fil-A closed their doors, and invited Christopher to come in to be manager for the day - while eating all the fries he likes.

Posting photos of the day on Facebook, his mother, a photographer, said she was overjoyed. 

'The wonderful research team at Cincinnati Children's Hospital actually researched and approved Chick-fil-A French fries to be safe once the potato trial was passed. 

'As a mom I was ecstatic, because now Christopher and Anna Claire could each have something they both enjoyed and that was safe for Christopher.'

She added: 'Christopher, got to live out his dream of owning a Chick-fil-A (for a day) and being able to eat and play inside an actual Chick-fil-A business. 

'He got to make and eat his french fries, work the drive thru, ring up mommies order and play in the play area. He told me it was his happiest day ever. 

'Many happy mom tears have been shed watching him glow a light I have not seen in a long time. Thank you to everyone that made this happen.' 

It has been a long journey to reach this point. 

Children with EOE require food tests for everything. But given the risks, the tests are onerous and can take a long time.  

The condition is caused by the body producing too many of a type of white blood cell in his esophagus and colon.

The cells' job is to kill bacteria and parasites, but the autoimmune condition causes them to react to foods, which in turn produces toxins and causes inflammation. 

It can be treated with modifying the diet to exclude certain foods, by taking steroid medications to reduce the swelling or by mechanically widening the esophagus.

EOE was only discovered in recent years so little is known about its exact cause.  

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