Parents often attribute their preschoolers’ rashes and runny noses to a food allergy, but in many cases they are putting the blame in the wrong place, a new study suggests.

The study, which followed more than 900 British children from birth to age 3, found that roughly 5 percent developed a food hypersensitivity based on clinical testing.

In contrast, one-third of parents in the study attributed symptoms like rash, diarrhea and nasal congestion to foods their child had eaten, the researchers report in the journal Allergy.

Food hypersensitivity includes both allergies, which are caused by an immune system overreaction, and food intolerance, which does not involve the immune system.

In this study, the most common culprits behind children’s symptoms were peanuts, eggs, wheat and milk. However, 80 percent of children who were hypersensitive to milk at one point outgrew the problem by age 3; the same was true of half the children with egg hypersensitivity.

It’s not particularly surprising that parents believed food allergies to be far more common than they actually were, according to the researchers.

“Parents often relate symptoms to what their children have eaten, and as we have found, this is often not related to the food,” senior researcher Dr. Tara Dean, of the University of Portsmouth in the UK, told Reuters Health.

The findings also suggest that food hypersensitivity may not be on the increase, as appears to be the case with asthma and hayfever, Dean said. A widely cited U.S. study conducted 20 years ago found that 7 percent of children developed food hypersensitivity by the age of 3.

Dean said there is “good evidence” that allergies, in general, have become more common in recent years, but there are no studies suggesting that food allergies are part of this trend.

SOURCE: Allergy, March 2008.