allergic rhinitis
"I am a retired physician. Every winter & spring I suffer with horrible congestive episodes, once becoming so dizzy, I barely could get out of bed just to go to the bathroom. I saw an ENT doc who diagnosed me with vasomotor rhinitis, and stopped my Claritin. Spring came around  & I was miserable again.  I saw an allergist who did multiple skin testing & concluded I had no allergies-urban irritants caused nasal mucosal swelling resulting in my congestion. When my symptoms got worse, I was sent for a CT scan of my sinuses, & was found to have chronic sinusitis. 
Every year I still have seasonal recurrences of sinusitis. My new PCP decided to try Singulair (Montelukast) along with antibiotics & I can now breathe out of both nostrils. Yay!"