Vasomotor rhinitis it also called idiopathic or irritant rhinitis.
Idiopathic means "of unknown cause."

In your case, it sounds like your doctor was referring to irritant rhinitis. In fact, sexual arousal can sometimes trigger of irritant rhinits symtpoms! Irritant rhinitis can also be triggered by smoke, environmental toxins, changes in temperature and humidity and stress.

The most important thing to remember is that this is not associated with any immune response. The biologic causes are unknown. Some research has found an association between vasomotor rhinitis and gastroesophageal reflux disorder (GERD, a common cause of heartburn), which some experts think may be due to a common defect in the nervous system that controls muscle action.

Talk to your doctor about how to treat this condition.