We all know people who are allergic to something, whether it's the hay fever sufferer who sneezes every summer, or someone who has to omit some foodstuff from their diet because it doesn't agree with them.
There is a massive market in allergy treatment and management. One estimate put the US market alone at $9.6 billion. The antihistamine market was put at $4 billion in 2006, and corticosteroids also at around $4 billion. That's big money in anyone's book so there is a huge commercial interest in persuading us that we have allergies that need treatment.
A few years ago I was with a group of eight colleagues on a training course and at our table alone there was a coeliac, someone allergic to nuts, another to lactose, and one who complained of egg allergy. On the incidence statistics alone, I was incredibly lucky to be sat at that table: I figured the probability to be around 1 in 5500 that they would all appear in a sample of eight.
Clearly someone wasn't really allergic to what they thought they were. The coeliac, suffering from years of gut problems, had been diagnosed with gluten intolerance following a long series of hospital tests, but the others? They'd self-diagnosed, associating an upset stomach with a foodstuff that affects a lot of people.
We're very vulnerable to the suggestion that we are ill and need treatment. The worried well syndrome encourages people to become very conscious of the state of their health even to the extent of seeking treatment for non-existent illnesses. But clearly that's not the whole story. Certainly having a dietary condition is almost a chic fashion item, making the owner in some ways special. But that rather fickle cause aside, why do so many people think they are suffering from allergies?