What causes a 'stuffy' or 'runny' nose when you have a cold?

Question

When humans get the common cold, a common symptom is a stuffy or runny nose. Is that the body's immune response or is that the virus's doing?

Answer 1

It's mainly caused by swelling of large veins and by an increase in vascular permeability that leads to an accumulation of fluids in the nasal mucosa. These effects are mediated, at least in part, by bradykinin and histamine, and can be counteracted by epinephrine. These mediators are part of the immune response to the viral particles.

You can read more about it here:

• http://www.cardiff.ac.uk/biosi/subsites/cold/commoncold.html
• Chernick-Mellins basic mechanisms of pediatric respiratory disease By Gabriel G. Haddad, Steven H. Abman, Victor Chernick (page 520)