Usually cold symptoms last for 1 to 2 weeks, although chest colds (bronchitis)
typically last 2 to 3 weeks. If your symptoms are not improving after 1 to
2 weeks, you may have an allergy, a complication of a cold, or some other
reason for your symptoms. You should contact your doctor if your cold symptoms
do not improve after 2 weeks, or anytime during your illness if you develop
a high fever; have difficulty breathing or swallowing; or experience severe
headache, severe fatigue, or a rash.