There's been a lot of reports in the media that there's been a large rise in the number of allergy-related health problems over the past decade. Some reports claim that there has been a 265% increase in the number of hospitalizations due to allergy related problems in the US over the past decade. Others say that certain allergies (such as peanut allergies) have doubled or tripled in recent years.
But then there's evidence against this. For example, although a US study showed that peanut allergies in children had doubled between 1997 to 2002, further digging reveals a less clear picture. For a start, it's only the one study. Secondly, the study was a survey (no actual allergy tests were taken). Thirdly, the rise was from 0.4% to 0.8%, which may not even be statistically significant.
Also, there's lots of articles speculating that media hype is largely responsible for this "rise" in allergies, with some people claiming it is nothing more than public mass-hysteria. (To put it into perspective: Only 150 people die each year in the US from allergy related problems. Only 10 from peanut allergies. Despite this, there is a large amount of media attention given to allergies, which may have led to people becoming unduly concerned.)
So where's the truth in all this? Has there been a genuine explosion in allergy related issues, is the public getting overly concerned due to irresponsible media reports, or has there been a change in how these issues are being treated by the medical profession?
Thanks for any solid answers!
Your question seems to focus on food allergies, which isn't the whole allergy picture.
Food allergies are tricky things; I myself am allergic to mushrooms. You've never quite enjoyed life until you've been intubated while conscious, let me tell you. But there does appear to be a increasing trend in both the UK and the US of peanut allergies.
EDIT to add:
The rise in peanut allergy has been well documented in a population-based study of 3-year olds in the UK, in which the prevalence of sensitisation to peanuts rose from 1.3% to 3.2% between 1989 and 1995.5 National surveys in the USA suggest that 1.1% of Americans-3 million people-are allergic to peanuts, tree nuts, or both.7,9 Similarly, data from a US National Health and Nutritional Examination Survey (1988-94) indicated that 8.6% of Americans have skin-prick test evidence of sensitivity to peanuts.10 In a newer study in the USA, the rate of peanut allergy increased from 0.4% in 1997 to 0.8% in 2002 in young children.7 In an epidemiological study in Canada, the estimated prevalence of peanut allergy in children was 1.34%.11
The Netherlands are also experiencing a rise in peanut allergy.
"At the end of the 19th century, allergy prevalence may therefore be estimated at 0.1% in England, as well as in the United States of America… By 1928 the prevalence of hay fever had risen from a few affected people to approximately 1%… Only a short time period later  that number increased to between 4 and 5 million, corresponding to a prevalence of 3%… In Switzerland, for example, the prevalence of hay fever rose from anestimated 0.82 percent in 1926 to 5 percent in 1958, and to approximately 10 percent by the 1980s… between 1980 and 2000 allergy prevalence reached an all-time high with up to 30% of the population being affected."
Another aspect to this question may be cross-contamination at factories/bakeries/etc that produce more than one type of food. Although the allergen may not be present in the food you are eating, it may be present at the factory where that food is produced.
Another area of concern is the potential, inadvertent introduction of an allergenic ingredient to a food (e.g., in a bakery that is manufacturing two food products on one production line, one product with peanuts and one without, where traces of peanuts, or peanut products, may end up in the product that does not normally contain peanuts).
In 2008, the FDA held a public hearing on food labeling and noted that contamination can occur during harvesting, manufacturing, transportation, processing and storage.