Thank you for your question.
I am Dr. Su S. and I will try my best to help you.
I am sorry for your symptoms.
There can be an allergy.
Chronic rhinitis, sinusitis can be there.
I would advise to take an examination by an ENT specialist.
As it is continuing for 6 months, a few tests can be taken.
CBC, allergy tests, X ray or scan can be taken.
Meanwhile, you can take zyrtec or claritin.
I hope this information will be helpful.
If you have any query, please feel free to ask.
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Wish your healthy life.