It means 21-month-old Toby's throat burns and becomes swollen whenever he swallows food.
Mum Suzanne, 37, says: "I made him a Thomas The Tank Engine cake for his first birthday party in February - all the children squealed when I brought it in, except Toby, The Sun of UK reported.
"Then as the other tots were eating jam sandwiches and chocolate fingers Toby quietly looked on.
"Even though he was only one, he knew he'd be ill if he ate any of the party food."
Shortly before his first birthday Toby was diagnosed with eosinophilic oesophagitis (EO).
The rare condition affects one in 2,500 children and is caused when the immune system wrongly attacks foods as a foreign body or a parasite - something which they think should not be there.
This leads to the upper digestive system becoming inflamed, causing vomiting, acid reflux, nausea and food aversion.
Toby is also allergic to dairy, wheat, soya, pollen, dust and an array of other things - these are the things his eosinophils, a type of white blood cells, think are attacking his body.
The cells are normally found in the blood system but Toby is quite unusual in that he also has them in his stomach.
Full-time mum Suzanne, who lives in Halifax with her partner Andrew Percival, 34, an IT consultant, daughters Lily, seven, and Isobel, four, says: "Toby was born when I was 38 weeks pregnant. I breastfed him but within a week, he repeatedly threw up his milk." Initially Suzanne thought the problem was reflux, which Lily suffered from when she was young.
The condition leads to partially digested food or liquid being regurgitated back up the oesophagus. She assumed that, like Lily, Toby would grow out of it when he moved to solid food. But to her dismay, things actually got worse.
"At 16 weeks old, Toby suddenly began to have screaming fits. He could screech hysterically for up to two hours at a time.
"Every time I fed him, he'd scream again.
"When I rushed him to hospital, I was made to feel as if I was an over-anxious mum. His screaming fits were dismissed as colic.
"When he was five months I tried him on solids but he'd choke, gag and vomit them back up."
Medics at Sheffield Children's Hospital tested the acid levels in Toby's stomach over 24 hours, which revealed he had reflux problems.
But the docs suspected there was more going on in his little body.
Further tests showed high levels of eosinophils in his oesophagus and tummy as well as in the usual place in his bloodstream. Suzanne was horrified when she was told this caused Toby to suffer awful burning sensations in his throat, making him sick or giving him diarrhoea.
She recalls: "I was relieved we finally had a diagnosis but as the months progressed, and we approached his first birthday, he wasn't crawling or rolling over and I knew he didn't have the strength.
"At 25 weeks old, he weighed 16lb 9oz and when he was one year old, he was 17lb 5oz - he'd put on less than a pound in six months."
Worried that Toby was getting weaker by the day, medics inserted a feeding tube up his nose and down to his tummy to try to get more food into him without hurting his oesophagus.
Immediately, he started to gain weight and began crawling and doing the normal things a baby his age should do. But he still wasn't getting enough vital nutrients.
In May 2010, medics inserted a permanent tube into his stomach which feeds him a small dose of special milk every hour for ten hours through the night. The special amino acid-based formula milk is stripped of everything he is allergic to and just contains nutrients.
His daily diet now consists of a pot of pureed fruit for breakfast, lunch is a stage one baby food pot of something savoury that contains no wheat or gluten, and his tea is the same again. And he takes 14 medications per day.
Suzanne says: "As I feed the girls fish fingers and chips, his little hand will grasp some of the food.
"He'll suck the fish but won't chew it. It's the same with pizza, he'll suck the crust but will not chew it or swallow any. Even plain boiled rice, which he loves, makes him sick. We tried him with stage two baby food and he gagged.
"Today Toby weighs 22lb - my daughters were 24lb at the age of one. He is two in February but has just gone into clothes for babies aged nine to 12 months old.
"Despite all this, he is a lovely, happy child and everyone who meets him can't help but think he is a gorgeous little bundle."
Toby's condition is incurable but doctors hope it will become less severe as he gets older.
And Suzanne reveals she is also optimistic for the future. She says: "The doctors say it's going to be a long road - we've got to now introduce one food at a time.
"But he's such a sunny lad, we know we'll all cope." - www.thesun.co.uk