Update: Nicki Brought up a great point in the comments section of this post regarding preparation method of the peanuts–there does seem to be a correlation between allergies and dry roast methods of preparation of the peanuts vs boiling, which is more common in Asian and in African cultures. Thanks, Nicki!
I did a bit of research–and it is true that the incidence of peanut allergies are increasing in the US and in Europe. I couldn’t find anything about Asia–but I am still looking. It’s estimated that 1.4 % of the US population has a peanut allergy–which is still relatively small. In addition, some children diagnosed with the allergy do outgrow it.
Theories for the increase include an introduction to peanuts at earlier ages–with most children consuming peanuts by the age of 1 as well as the increased intake of peanuts overall.
Food programs for children, such as WIC offer peanut butter as a supplemental protein source for both women and their children ages 1-5. We are also purchasing more snack foods than ever before and many contain peanuts.
As far as other tree nuts go–only a test from your doctor can tell you whether or not the allergy extends beyond peanuts alone. As an RD–most of my patients that were allergic to 1 item seemed to be allergic to others–so in my opinion it is smart to be tested for food allergies if you see any reaction to eating a particular food.
I would be very interested to see what the data is for Africa–a country that relies heavily on peanuts in their daily diet. Surely, peanuts are introduced at early ages there as well.