Air Travel, Colds, and Sinus Infections
People with severe colds and sinus infections know that air travel can be painful. During a flight, the air pressure in the sinuses (collections of air within the facial bones) and middle ear must equilibrate with the cabin pressure inside the airplane, which changes during ascent and descent. Certain infections and other conditions can cause blockage in the Eustachian tube (which connects the middle ear to the back of the nose and maintains equal air pressure on both sides of the eardrum) or in the sinus openings, and this restriction to the flow of air can prevent the equalization, or equilibration, of pressure and result in pain. Examples of conditions blocking the equilibration of air pressure in the ears or sinuses include congestion caused by colds or allergies, middle ear infections, and sinus infections.
Pain is not the only symptom that may occur when the Eustachian tube is blocked. The pressure changes inside the middle ear may sometimes lead to vertigo (a sense of "spinning"), tinnitus ("ringing" in the ears) or hearing loss. In severe cases, rupture of the tympanic membrane (eardrum) may occur.