Two years ago my mother almost killed my daughter. With a chocolate cake.

It was at a family party (marquee on the lawn, Champagne, the works) thrown to celebrate the publication of my book, Dangerous Love, which ended with me abandoning my speech to the assembled relatives and exiting the party in an ambulance.

We endured a terrifying dash to the nearest hospital, with my poor pale girl, who had already been revived once with adrenaline, appearing to lapse into unconsciousness. When we arrived, she vomited all over the floor, then sat up and said brightly, 'I feel much better now', as children do when you get them to the doctor's. Needless to say, I was a nervous wreck.

Since Allergy UK has been promoting Food Allergy and Intolerance Week, I thought I'd paint a personal picture of what living with food allergies is like. Two per cent of the population suffers from food allergies, which can, at worst, be fatal (as opposed to food intolerances, which are more widespread but less severe and tend to be implicated in conditions such as migraine, chronic fatigue and IBS).

Everyone knows about peanut allergy, but the range of foods that can trigger reactions is surprising. Common allergens are nuts, dairy, eggs, soya, sesame, seafood and even fruit and vegetables (celery and kiwi are notable culprits). Food allergies tend to show up when children are very young but they can develop during teens or adulthood, even if you've been able to eat that particular food without a problem previously.

All it takes is a bite, sometimes even a sniff, to trigger an extreme allergic reaction, known as anaphylaxis, in susceptible people. The mouth, tongue and throat may swell rapidly, preventing breathing and swallowing, and the person may go pale and floppy and lose consciousness due to a sudden fall in blood pressure. Under these conditions, adrenaline must be administered, and quickly.

Up until the cake incident, antihistamine had been sufficient to treat our daughter's allergies (usually manifested by vomiting, hives and flushing of the skin). This time, after being sick, she said her mouth hurt. She was white as a sheet and her speech started to go, then she went floppy, sinking back into our arms.

I knew I had to act. Although I'd practised with a training device, using the EpiPen (an auto-injector of adrenaline) for the first time when my child was collapsing and my hands were shaking was a testing moment. I did it correctly - all the procedures we had in place worked - but it was a scary experience, all the more so because we didn't know what had triggered her reaction.

My mum had been well briefed about my daughter's allergy to eggs and nuts - I'd even given her the special allergy-friendly cake recipe myself - and she swore she'd triple-checked everything. Sitting in the ambulance, I blamed myself. The cocoa powder I'd recommended had the ubiquitous 'May contain nut traces' warning on it and, having used it many times before, I'd taken a calculated risk that contamination was unlikely. It seemed I'd been wrong.

It wasn't until ten months later, by which time we'd made two trips to Leeds General Hospital for a raft of further allergy tests, that I recalled an incident several years earlier when our daughter had been given royal icing at a birthday party, which had made her poorly. I rang my mother and asked her what icing sugar she'd used. She dug it out from the back of the cupboard. It turned out to contain egg white. She was mortified.

The problem is, most people don't have to operate at the same level of awareness as us. Icing sugar, sausages, ice-cream, biscuits, meatballs, pasta, chicken nuggets, cereal, sweets, gravy granules, crisps, soup and even bread can contain egg, so label-reading is a way of life. You can't afford to be complacent. Formulations change and production lines alter, so you have to check every time.

It takes me twice as long to get round the supermarket as most people because I spend so long squinting at the small print on the back of packets.

Fortunately, new EU food labelling regulations came into force in November 2005, requiring food manufacturers to declare allergens clearly, which makes assessing the risk of contamination easier. Tesco, in particular, has done a good job.

Food allergies are stressful to live with - more so, according to some research, than living with cancer. I know of parents who have tied themselves in knots trying to protect their kids, with the result that the children were nervous and the families rarely went out or had fun.

Life isn't risk-free. Children have to learn to cope by themselves as they grow up and we do them no favours by being too clingy. Our friends are understanding, which helps enormously, but most of all, we've had to learn to trust our child, who, at eight, is amazingly mature about her allergies. She goes off to parties and sleepovers without a qualm; it's me that finds letting go hard. I still jump when the phone rings. It goes with the territory.

Updated: 16:20 Friday, January 27, 2006