When I move away from someone who's having a cigarette, it's not because I'm anti-smoking, it's because a wisp of smoke could make me dangerously ill. When I cross the road to avoid a group of young men, it's not because I'm intimidated but because I'm allergic to aftershave. Phoning the chef before going to a restaurant isn't faddy, it's a necessity. I wish I could say one or two allergens are the culprits, but my list of potentially fatal substances is very long and – what is most alarming – growing all the time. Doctors say it's very rare – each time I have an allergic reaction, it makes me even more sensitive to allergens and the reactions get worse.

Fifteen years ago my life was relatively allergy free – mosquito bites would blister, which made camping uncomfortable, and cheap jewellery caused a rash, but it was hardly life-altering. Then I was stung by a bee or wasp in the garden and suddenly felt very ill. I went to lie down and woke up three days later. I live on my own and didn't know anything about allergic reactions so as I drifted in and out of consciousness, aware that I was struggling to breathe, I decided I must have flu. When I noticed the stung area was blistered and angry-looking I went to the doctor. A referral to an allergy specialist confirmed that not only had I become allergic to wasp and bee stings but the reaction had set my whole immune system on red alert.

As the months went by, more and more previously innocuous substances brought on reactions – at the most extreme, anaphylactic shock, but also nausea, burning rashes, aching limbs, hallucinations, fainting and heart palpitations.

It is easier to say what I'm not allergic to than what I am. A trip to the supermarket poses a problem. Take a tin of baked beans: relatively harmless, you'd think, but as well as being allergic to base metals, which rules out canned food, the ingredients in the sauce includes spices. This may mean cinnamon, which is a no-no for me.

I'm allergic to additives and preservatives, which makes eating umpteen foods impossible. A mouthful of alcohol knocks me out and leaves me with an instant hangover – I'm a very cheap date. My allergy to formaldehyde prevents the use of everyday toiletries, cosmetics and cleaning products.

It's almost impossible to minimise my contact with allergens. I carry an EpiPen which delivers a dose of adrenaline to try to halt the reaction, but last year I had five major reactions ending in anaphylactic shock. Small things can have a huge impact – deodorant made my body and arms come out in painful, itchy hives. I had to walk around holding my arms away from my body like a monkey.

My life revolves around controlling my exposure to potential allergens. Staying at home is often the preferred option. I enjoy horse riding but am allergic to both horses and hay. Strenuous exercise is best avoided anyway as I'm allergic to my own sweat. I live on my homegrown fruit and veg, make my own bread and have eggs laid by my hens. Unfortunately a red ants' nest appeared by the coop and last summer I felt one running up my trouser leg. I soon felt a searing pain travelling through my body towards my heart, which began jumping. I now wear wellies to collect my eggs.

The physical side is something I have learned to deal with but the social repercussions are painful. People look affronted when I back away at the first whiff of perfume and I feel terrible having to explain why I can't eat or drink at parties. I have a small group of caring friends who look after me when we're out. They're like my bodyguards, but I do sometimes feel like a child.

I'm single, and I imagine I'll stay that way. I don't think my allergies have stopped me meeting anyone but I suppose it's best I haven't – it would be too much to ask of someone to adapt to my lifestyle.

I'm 40 now and luckily I like being on my own; I can work from home and sit tapping on the computer in the quiet. I wouldn't recommend it as a life choice but my allergies have forced me to have a new perspective. Through meditation I have discovered an inner calm; there's nothing better than leaning out of an open window at night, the river quietly flowing past, and the sound of silence. What can I do but smile?

• As told to Emily Cunningham.

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