According to the Mayo Clinic, the average adult suffers from the common cold two to four times per year. The common cold is responsible for symptoms including runny noses, fever, fatigue and sneezing. According the Children's Hospital of Pittsburgh there will be an estimated 1 billion colds in the United States during the course of a year. Under normal circumstances, you recover from the virus causing common colds with no long-term or adverse affects. In some rare cases, the cold virus produces prolonged and harmful symptoms.
The common cold works by primarily targeting the respiratory system that is responsible for the intake of oxygen and output of carbon dioxide. The respiratory system consists of the lungs, pharynx, larynx, trachea, bronchi and nose. If any part of the system is compromised, there is potential for serious complications. Prolonged colds can lead to wheezing, secondary infections such as pneumonia, sinus infections and croup in children. Wheezing produces a whistling sound during breathing and generally signals a problem in the lungs. Shortness of breath may be associated with this symptom. This symptom could mean that you are not able to inhale an efficient amount of air.
In children especially, long-term colds can cause ear infections. Left untreated or undiagnosed, the infections can lead to severe and permanent damage to the structures of the ear. In rare cases, partial or total hearing loss may occur. While ear infections are more common in children due to the underdevelopment of the structures of the ears, adults are susceptible to ear infections as well. Symptoms of ear infections include fever, foul-smelling drainage, itching and pain.
Loss of appetite is a symptom that is sometimes associated with the common cold. Individuals infected with the virus causing the cold often suffer a lack of appetite and find it difficult to eat. If this continues over a prolonged period of time, you are at risk for losing a significant amount of weight. It is important to be very conscious of the nutritional value of meals consumed while suffering from a cold for this reason. In addition, the fluid and electrolyte balance within the body may be compromised due to the lack of food and fluid intake. This imbalance can cause vomiting, diarrhea and damage to the internal organs, according the National Library of Medicine.