There is no permanent cure for allergic rhinitis, but, the symptoms tend to decrease or even subside as a person ages.
People that have developed rhinitis in early childhood, often have the worst symptoms at age of 18, but these diminish during adulthood.
People who develop allergies after age 20, however, tend to continue to have hay fever at least into middle age.
Immunotherapy won't cure the allergic rhinitis, but will lead to good control of its symptoms.

Can you tell me a bit more about immunotherapy?