The common cold can occur any time of year, in both warm and cold weather seasons. Flu season generally runs during the colder months in the Northern hemisphere, from November through March. Annually, 25 million people in the United States seek treatment for influenza, of which up to 200,000 require hospitalization. There are between 40,000 and 60,000 flu-related deaths annually. Though the common cold and the flu are the most well-known respiratory tract illnesses, there are other non-specific respiratory illnesses, known as respiratory tract infections that often occur.
The term upper respiratory infection, or URI, refers to acute infections that affect the nose, sinuses, pharynx, larynx, paranasal cavities, trachea and bronchi. Although the common cold falls under this category, other illnesses do as well, including pharyngitis, sinusitis and tracheobronchitis. Although the flu does involve the upper respiratory tract, it is a systemic illness and therefore does not fall under the category of upper respiratory infection.
Upper respiratory symptoms generally begin to develop between 1 and 3 days after exposure. Symptoms can vary in severity, often starting out with one or two mild symptoms and shortly after increasing in severity. Symptoms of an upper respiratory tract infection in adults generally include:
Additional symptoms in adults that are less common but may occur include:
Children infected with an upper respiratory tract infection may exhibit different symptoms than adults. The most common symptoms for children are sore throat, fatigue, irritability, loss of appetite and cough.
The majority of upper respiratory tract infections are caused by a viral illness. The most common viruses responsible for upper respiratory infections are:
Bacterial infections can also cause upper respiratory tract infections, though they are less common. Bacteria that can be responsible for upper respiratory illnesses include:
Both viral and bacterial infections can be transmitted via infected secretions. Infection can be spread by hand-to-hand contact (followed by placing the hands or fingers in the nose or eyes, or on the face) or via airborne contact from sneezing or coughing. Bacterial infections of the upper respiratory tract such as sinusitis and bronchitis often develop following an infection with the common cold.
There are several risk factors that make an individual more susceptible to developing an upper respiratory tract infection. Common risk factors include:
The first step in diagnosing an upper respiratory tract infection is determining if the underlying infectious agent is viral or bacterial. Although the majority of cases are due to viral agents, it is important to rule out bacterial infection which would require antibiotic treatment. There are limited diagnostic tests available to diagnose a viral infection of the upper respiratory tract. The majority of individuals do not need treatment for viral infections; however, those who suffer from immunodeficiency may need antiviral therapy. Doctors may perform viral cultures, rapid antigen tests or nasopharyngeal swab to determine which viral agent is causing the infection in Immuno-compromised individuals.
If mononucleosis-type illness or influenza is suspected, serological tests may be performed. A pharyngeal swab (throat culture) will be performed if strep infection is suspected. Individuals with acute sinusitis or those who have intracranial or orbital complications may require a sinus puncture.
Treatment for upper respiratory tract infection depends on the underlying cause. If the infecting agent is viral, treatment will involve basic home care therapies. If the illness is due to a bacterial infection, antibiotic therapy will be started. Depending on the antibiotic used and the severity of the infection, therapy will generally last anywhere from 5 to 10 days. Additional medications may be prescribed do treat the symptoms of upper respiratory tract infection. Decongestants, throat lozenges and pain relievers can be effective in reducing symptoms.
Adults who are diagnosed with an upper respiratory tract infection should get plenty of rest and stay well hydrated. If hoarseness is present, resting the voice is also important.
Children suffering from an upper respiratory tract infection should be encouraged to nap often and rest throughout the day. Eating soft foods can help ease pain that occurs when swallowing. It is especially important for children to drink plenty of fluids throughout the day as they are more susceptible to dehydration than adults. Children may have a decreased appetite, so it is important to offer them food often throughout the day and encourage them to eat small amounts often.
Upper respiratory tract infection is a common illness that occurs in both adults and children. Both viral and bacterial infections of the upper respiratory tract can occur. With proper treatment and homecare, the illness generally clears up in a few days with little to no complications in otherwise healthy individuals.