The treatment is;
1) nasal saline spray; do not need prescription for it.
2) nasal corticosteroids / nasal cromolyn / nasal antihistamines may also be needed,
3) oral leukotriene inhibitors and
4) oral antihistamines; you may try Claritin D which is over the counter.
Please feel free for your follow up questions.
I would be happy to assist you further, if you need any more information.