Some factors that may increase the risk of developing hay fever include:

High IgE Levels

Hay fever usually impacts sufferers from an early age. Toddlers (under 6 years old) who are tested for Immunoglobulin E (IgE) levels will be at risk for hay fever if serum IgE is greater than 100 International Units per milliliter. 

Family History

A family history of hay fever or asthma increases your risk for developing allergies.

Environmental Exposure

Some studies have shown that those in a higher socio-economic class are at a greater risk for developing hay fever. Experts believe that this could be due to either an increased exposure to allergic rhinitis allergens, including dust mites and pollen, or due to certain vaccination practices, diets, and use of antibiotics which skew the immune system towards the development of hay fever.  

Learn more:

What causes hay fever?

Treating the symptoms of seasonal allergies.

Tests to diagnose hay fever and allergies.