Complications

Complications

Colds rarely cause serious complications. In about 1% of cases, a cold can lead to other complications, such as sinus or ear infections. It can also aggravate asthma and, in uncommon situations, increase the risk for lower respiratory tract infections.

Ear Infections. The rhinovirus infection, a major cause of colds, also commonly predisposes children to ear infections, possibly by obstructing the Eustachian tube, which leads to the middle ear. Viruses may even attack the ear directly. In one study, 74% of patients with rhinovirus colds had pressure abnormalities in their middle ear.

Sinusitis. Between 0.5 - 5% of people with colds develop sinusitis, an infection in the sinus cavities (air-filled spaces in the skull). Sinusitis is usually mild, but if it becomes severe, antibiotics generally eliminate further problems. In rare cases, however, sinusitis can be serious.

Lower Respiratory Tract Infections. The common cold poses a risk for bronchitis and pneumonia in nursing home patients and other people who may be susceptible to infection. Some experts believe that the rhinovirus may play a more significant role than the flu in causing lower respiratory infections in such people.

Aggravation of Asthma. Rhinovirus infections can aggravate asthma in both children and adults and has been reported to be the most common infectious organism associated with asthma attacks. Some studies have reported the common cold being associated with between 33 - 71% of severe asthma episodes. Research suggests that colds promote allergic inflammation and increase the intensity of airway responsiveness for weeks.

Complications of Influenza

In general, the flu is usually self-limited and not serious. About 1% of people who contract the flu are hospitalized. An estimated 36,000 people die each year of influenza-related complications. People at highest risk for serious complications are those over 65 years old and those with other medical conditions. Influenza A is the most severe strain and causes an estimated average of 142,000 hospitalizations per year. Influenza B tends to be milder.

Pneumonia. Pneumonia is the major serious complication of influenza and can be very serious. It can develop about 5 days after viral influenza. More than 90% of the deaths caused by influenza and pneumonia occur among older adults. The growing elderly population will most likely account for an increase in the number of deaths from influenza. Nursing homes patients are especially hard-hit by flu epidemics, with fatality rates as high as 30%. Flu-related pneumonia nearly always occurs in high-risk individuals, such as the following: