EXHAUSTED and peckish after an energetic game of tennis, Caroline Glennie could not resist the offer of a homemade treat from her playing partner. She casually bit into the chocolate-coated millionaire's shortcake, unaware she was putting her life in danger.
Within seconds, her immune system had started to rebel. Soon, she was gasping for air, heart racing, her skin covered in burning red spots.
It wasn't the first time her serious food allergy had left her perilously close to disaster. And it wouldn't be the last, either.
For Caroline is among an increasing number of food allergy sufferers who live knowing they are just a bite away from a potentially fatal anaphylactic shock.
While as many as one in 70 children in the UK has, like Caroline, a potentially fatal allergy to peanuts, an even greater number of people believe their day-to-day health is adversely affected by the food they eat. Victoria Beckham and actor Orlando Bloom both claim to be intolerant to dairy foods, while actress Rachel Weisz, right, and Posh's former bandmate Geri Halliwell are both said to have eliminated wheat from their diet. But while their intolerances may cause discomfort, bloating or migraines, Caroline's allergy could kill her.
She was just nine when, without warning, she suffered her first attack. "I didn't know what was wrong," says Caroline's mother Pam. "I thought maybe she had been stung by something, so I grabbed an anti-histamine tablet and an inhaler of mine and put her in a cool bath - I didn't know what else to try.
"Next day the doctor said I had been very silly, that she could have died, and my blood ran cold."
Tests revealed a host of severe allergies to everyday ingredients - peanuts, peas, beans, shellfish, lentils, barley - so bad that consuming just a tiny amount could spark a life-threatening reaction.
Now aged 25, Caroline, a physiotherapist, lives in a constant state of alert. "I've learned to live with it," she explains, "but it is a bit of a nightmare. I've got to read the packaging of everything. It makes food shopping a real chore and my diet is really restricted.
"It's worse when I'm eating out. You don't know how seriously restaurants take you and you don't feel you can trust everything you eat."
Like many sufferers, Caroline carries an EpiPen containing a dose of adrenalin, which can be injected if an attack occurs. She has suffered four other serious attacks since her first, including the one following her tennis match. It later emerged the treat was made with flour containing minute traces of peanut. Another attack happened after she made a jam sandwich using a knife which had previously been dipped in peanut butter. She ended up in hospital.
"A reaction takes over your body," she adds. "You can't breathe but it's the way your heart races that is the most scary."
Caroline, of Melbourne Road, North Berwick, is among the two per cent of the population diagnosed with a severe food allergy which causes the immune system to over-react to what it sees as a threat to the body.
In addition, more than 40 per cent of the population is said to suffer from some kind of food intolerance, with symptoms ranging from headaches and sickness to fatigue, says charity Allergy UK, organiser of this week's Food Allergy and Intolerance Week. The most common offenders are dairy products, yeast, eggs and grains, especially wheat. Other key "trigger" foods include garlic, nuts, soya beans, oats, lentils, kiwi fruit, chilli pepper and sesame seeds. Yet the charity claims many health professionals do not take the problem seriously enough - a suggestion apparently backed up by a survey which suggests many doctors believe food intolerance is largely in the mind.
"Too often we feel symptoms are not taken seriously by doctors because they're given insufficient training," says spokeswoman Muriel Simmons, who has an extreme allergy to garlic. "This means sufferers may be forced to turn to alternative methods for diagnosis and end up using costly, clinically unproven tests which could damage their health."
Anaphylactic Campaign spokesman David Reading, whose 17-year-old daughter Sarah died in 1993 after eating a dessert made with a small amount of peanuts, says food allergies can emerge at any age. On the plus side, however, sufferers can grow out of the problem. He adds. "A food allergy is a potentially serious condition but it is manageable as long as you keep your wits about you.
"But while product labelling has generally improved, there is still no requirement for restaurants, hotels, takeaways and bakeries to label their products - yet they are where some of the fatal reactions occur."
• AllergyUK has a helpline and a website. Call 01322 619 898 or visit www.allergyuk.org
The Anaphylaxis Campaign is at www.anaphylaxis.org.uk, call 01252 542029.