Allergens are substances that ‘trick’ our immune system into thinking it is being invaded, which in turn makes it overreact. The body tries to protect it from these substances, and cells release histamines (and other substances) to defend itself.
Allergic reactions have increased in recent times, and it is not entirely known why. One theory is that our bodies suffer higher levels of inflammation in modern times which makes our bodies react more violently to intruders.
Essential oils can be great for reducing inflammation and improving the immune sytem.
Great essential oils to use in your burner or diffuser for hay fever are:
Peppermint
Basil
Lemon
Tea Tree
Eucalyptus
You could also try adding a few drops of any of these essential oils to some full fat milk and pouring it in the bath when you are soaking.