The common cold is generally mild and self-limiting with most symptoms generally improving in a week. Half of cases go away in 10 days and 90% in 15 days. Severe complications, if they occur, are usually in the very old, the very young, or those who are immunosuppressed.
Types of sick sinus syndrome and their causes include: 1  Sinoatrial block. Electrical signals move too slowly through the sinus node, causing an abnormally slow heart rate. 2  Sinus arrest. The sinus node activity pauses.  Bradycardia-tachycardia syndrome.
An allergy to mold and mildew causes sinus headaches and nasal congestion. Headaches and congestion from mold and mildew are the result of a mold allergy, according to the Asthma and Allergy Foundation of America. A mold allergy is defined by MayoClinic.com as an overreaction of the immune system to mold spores.