RARE ALLERGY CAN KILL GIRL IN MINUTES.
The 14-year-old schoolgirl from Cork goes into toxic shock if she eats an apple - near to a birch tree.
Bizarrely, Grace has no reaction to either the fruit or tree pollen on their own.
But together they form a potentially deadly combination.
The allergy developed suddenly as Grace played outdoors with a bunch of friends.
She began to complain of itchy eyes. Then within seconds her head swelled up like a football and hives developed all over her body.
Mum Margaret was horrified when she opened the door to find Grace standing outside.
She said: "If it hadn't been for her clothes and her hair, I wouldn't have recognised her.
"Her head was so swollen I thought she had been beaten up."
Grace was rushed to hospital where baffled doctors carried out tests and said it was probably an allergic reaction.
They injected her with adrenalin and antihistamines. But it still took two or three days before Grace's body returned to normal.
Margaret added: "We didn't think much more about it until the following year the same thing happened. Grace ran home from a nearby park with her head swollen beyond recognition. Then she began to wheeze and said, 'I can't breathe'.
At hospital she was immediately put on an oxygen machine as her windpipe began to close because of the swelling.
"The doctors told me it was very serious," said Margaret. "Grace had gone into anaphylactic shock, a life-threatening allergic reaction. There is no doubt she would have died if I hadn't got her to hospital."
She and hubby Maurice were devastated their oldest child had such a deadly allergy, especially as doctors did not know what triggered it.
Margaret said: "I was living on pure fear. Everytime she ate I waited for something to happen. We didn't know what foods to avoid.
"I would creep into her room at night with a torch to make sure she was OK. It was a huge strain."
Finally Grace was referred to Ireland's leading allergy expert, immunologist Dr Bruce Mitchell, at Dublin's Blackrock clinic. After three weeks of tests, he discovered she was allergic to birch pollen in a cross-reaction with apple.
"It was a huge relief to know what caused it," said Margaret. "That was half the battle. The other half was learning to live with it."
Grace no longer eats fruit in the pollen season and has given up apples and nuts for life.
She must carry a syringe filled with adrenalin with her for the rest of her life in case she suffers an attack.