Dataset of allergies

Question

I'm looking for a dataset containing the following:

• for each country, for each allergy types, number of humans affected by the allergy.
• if possible, break down per gender and age.

Answer 1

A list of statistics is available for U.S. persons:

• Medical treatment triggered by allergies and hay fever.
• Allergy by age and ethnicity for 1998-2012 (specifically at 205.207.175.93/HDI/TableViewer/tableView.aspx?ReportId=59)

An interesting related article about the need for more data on allergy prevalence in developing nations may be informative.