Seasonal allergy, hay fever or allergic rhinitis, often affects us the most during spring or when the weather starts to get warm. It affects roughly 10-30% of the people in western countries.
It is a result of our immune system treating foreign substances such as spores and pollens from the plants as harmful objects and triggering immune responses to expel them from the body.
These spores and pollens are invisible to our eyes, but are detected by our immune system.
Antibodies in our bodies are released and trigger release of histamine that causes many allergy symptoms.
- running nose (clear, watery)
- itchy nose, eyes, throat, mouth
- stuffy nose
(also see: Do I have a cold or allergy?)
- Pollens and spores from flowers, trees, grass, weeds, and molds
Other common allergens includes:
- Pet dander
- Dust mites
Fortunately, this "over reaction" of our immune system is not forever. Over time, sometimes decades, we no longer develop immune responses to the same allergens. This explains why we may suffer hay fever younger and are symptoms free later in life.
However, we may develop hay fever later in life as well, due to global warming. New breeds of plants and increased amount of pollens and trigger hay fever symptoms.
Under the same principle, we may develop hay fever when we travel or move to a new environment.