The charity Allergy UK told FoodNavigator.com that they are seeing more cases of oral allergy syndrome (OAS), which is an allergic reaction to food limited to the lips, mouth and throat.
Fresh fruit, vegetables and nuts are common causes and foods that are more likely to trigger it include celery, carrots, tomatoes, apples, peaches, pears and hazelnuts.
The syndrome is linked to hayfever, which affects two in every 10 people in the UK. Meanwhile recent figures show peanut allergies affects one in 50 young people in the UK.
This means that OAS is likely to be more prevalent than peanut allergies, which are far less common, according to Allergy UK spokeswoman Lindsey McManus.
She told FoodNavigator.com: “It may well be that because the incidence of hay fever is very high, it (OAS) is probably going to be higher than peanut allergies.
“We haven’t got any statistics but we are seeing more of it across the board (among adults and children).”
Symptoms include itching and swelling of the lips and itching, tingling and swelling of the mouth and throat which typically start within minutes of eating and settle down within an hour.
However, it is not considered a serious problem unless swelling in the mouth or throat affects breathing, which is very unusual.
The syndrome is linked to hayfever because pollens from trees (especially Birch), grasses and weeds contain proteins of similar structure to those present in certain fruit, vegetables, nuts and spices.
These proteins are recognised by the immune system of a hayfever sufferer and can trigger an allergic reaction when they eat a food that shares the same protein as the pollen.
McManus said the body sees it as being the same allergen and added: “When people eat apples, particularly at the birch pollen time, or some stone fruits the allergen in them causes a reaction.”
However, she said that it probably wouldn’t be an issue in processed food because cooking or heating breaks the allergen down. Also peeling or cutting the food and leaving it for 10 minutes can reduce the reaction, although sufferers are advised to avoid foods that cause the reactions.
Similarly to introduce labels warning consumers that products may contain fruit or veg, as is the case with nuts, would be “taking it a bit too far”, said McManus, because OAS is not life threatening like anaphylaxis and it would be a very difficult to police.
Fruit and veg allergy epidemic
Meanwhile other British allergy specialists have reported a rise in cases of OAS, particularly among children.
Dr Pamela Ewan, an allergy consultant at Addenbrooke's Hospital in Cambridge, told the BBC news website: "We have seen a big rise in the number of cases in the past four to five years.
"It is a bit like the peanut allergy was the epidemic of the 1990s. I think fruit and vegetables are becoming the epidemic now.
"In terms of numbers, fruit and vegetables are the new form of peanut allergy.”
Also according to the BBC, records indicate that in a six year period, the rate of final clinically diagnosed cases of OAS rose from about one per 100,000 of the population in the Cardiff and South Wales area, to five in the year 2007/8.
However the reason for such increases could be improved diagnostic procedures.