How is a common cold diagnosed?

Doctors are usually able to diagnose a cold from the typical symptoms. Often an individual will diagnose a cold without seeing a healthcare provider. If a provider is seen, he or she will examine the person's head, neck, and lungs. The provider will also look for signs and symptoms of more serious respiratory illnesses, such as pneumonia or bronchitis. There are no laboratory tests readily available to detect the cold virus. However, a doctor may do a throat culture or blood test to rule out a secondary infection.

Influenza is sometimes confused with a cold, but the flu causes much more severe symptoms and generally a fever. Allergies to molds or pollens also can cause a runny nose. Allergies are usually more persistent than the common cold. An allergist can do tests to determine if the cold-like symptoms are being caused by an allergic reaction. Also, some people get a runny nose when they go outside in winter and breathe cold air. This type of runny nose is not a symptom of a cold.