Brief Answer:
Patch test to specify the allergen

Detailed Answer:
Hi,

As the name says allergic rhinitis is a result of contact with a particular allergen. The allergen could be anything be it dust, weed, pollen. As soon as the allergen that is invisible sticks to the nasal mucosa it triggers a sequence of events leading to runny nose, sneeze, sore throat. So immunity and fighters are busy trying to defend this event while the bacteria and germs try to gain entry into the body. This can cause infection with pus discharge, cough and more complications.

So to prevent this permanently,
1) Identify the allergen with the help of a patch test done by Dermatologist / Allergist.
2) Once the allergen is identified, a desensitization therapy can be planned against that particular allergen as Plan A. A Plan B is where you should try to avoid all the situations and surrounding that you may possible to come across these allergens.
3) As soon as you get home / office you should immediately wash the nasal mucosa, ears, eyes with cold water so that the allergic reaction does not trigger.
4) Cetrizine (anti histamines) like drugs would not prevent an already triggered allergic reaction. So you should take them even before the release of the antihistamines. That means you are aware that you came in contact with the known allergen so you should take Cetrizine like drugs even before the symptoms start.

The next step is to see an Allergist / Dermatologist who does patch testing and trained in Desensitization therapy.

Hope this helps you plan how to go further.

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