Runny nose or rhinitis affects almost everyone.
Symptoms include nasal drainage either out the nose or down the back of throat, and itchiness (in allergic rhinitis both the eyes and nose itch).
Here we list common causes rhinorrhea (runny nose), focus on allergic rhinitis and note the potential for secondary sinus infection.
Common causes of rhinitis:

• allergies: grass, weeds, trees, pollen, molds, dust, animal dander, cockroaches
• irritations: smoke, exhaust, perfume
• food: hot and spicy.
  e.
  g.
  Buffalo wings or Tai food.
  
• medicine: overuse (>5days) of decongestant nose spray, some anti-hypertensives, erectile dysfunction meds, anti depressants, anxiolytics, NSAIDS and aspirin.
  
• other: nasal polyps, septal deviation, cerebral spinal fluid (CSF) typically following trauma or surgery - may be bilateral or unilateral, systemic problems like Wegeners Granulomatosis, and atrophy of the mucosa in the elderly.
  

Tidbits on runny nose:

1. Allergies usually include nasal itchiness and itchy red eyes whereas irritants and other causes may not involve the eyes.
   
2. Sneezing reflex: Sneezing with sudden bright light or sudden change in skin temperature is a normal reflex.
   

How to diagnose allergic rhinitis:

1. identify allergens or triggers (seasonal or perennial)
2. identify symptoms: sneezing, runny nose, postnasal drip, itchiness, itchy watery eyes)
3. positive family history
4. history of asthma
5. absence of fever, body aches and other head cold or flu like symptoms.
   

Allergic rhinosinusitis Nasal mucosa and sinus mucosa are continuous.
When the nasal tissue becomes swollen from allergy, the portals from the sinuses close.
Mucus becomes trapped in the sinuses causing pooled stagnant mucus which has a greater potential to become infected with bacteria Sinus infection signs and symptoms include

• fever
• facial bone or tooth pain
• yellow or greenish drainage (although abnormal color does not always mean bacterial infection).
  If severe the mucus can drain down the back of the throat and cause throat or stomach irritation or upset.
  
• recent history of allergic rhinitis or head cold.
  

If you have allergic rhinitis, it is important to treat the symptoms and avoid the triggers if possible.
Good management will result in improved quality of life and decreased risk of sinus infection.
In part II of Is Your Nose Running?, we will discuss treatment options for allergic rhinitis.
Stay tuned.