Common Cold Health Article

Definition

The common cold is a viral infection of the upper respiratory system, including the nose, throat, sinuses, eustachian tubes, trachea, larynx, and bronchial tubes. Although over 200 different viruses can cause a cold, 30–50% are caused by a group of viruses known as rhinoviruses. Almost all colds clear up in less than two weeks without complications.

Description

Colds, sometimes called rhinovirus or coronavirus infections, are common, frequently occurring illnesses. It is estimated that the average person has more than 50 colds during a lifetime. Anyone can get a cold, although preschool and grade school children catch them more frequently than adolescents and adults because they have not been exposed to the cold viruses and developed immunity. Repeated exposure to the viruses that cause colds creates partial immunity.

Although most colds resolve on their own without complications, they are a leading cause of visits to the doctor and of time lost from work and school. Treating symptoms of the common cold has given rise to a multi- million dollar industry in over-the-counter medications.

Cold season in the United States begins in early autumn and extends through early spring. Colds occur more frequently during this period because people tend to spend more time indoors where it is easier for viruses to spread from one person to another. Although it is not true that getting wet or being in a draft causes a cold (a person has to come in contact with the virus to catch a cold), certain conditions may lead to increased susceptibility. These include:

• fatigue and overwork
• emotional stress
• poor nutrition
• smoking
• living or working in crowded conditions

Colds make the upper respiratory system less resistant to bacterial infection. Secondary bacterial infection may lead to otitis media (middle ear infection), bronchitis, pneumonia, sinus infection, or strep throat. Patients with chronic lung disease, asthma, diabetes, or a weakened immune system are more likely to develop these complications.

Causes and symptoms

Colds are caused by more than 200 different viruses. The most common groups are rhinoviruses and coronaviruses. Different viruses are more infectious at different seasons of the year, but determining the exact virus causing the cold is not important for purposes of treatment.

People with colds are contagious during the first two to four days of the infection. Colds pass from person to person in several ways. When an infected person coughs, sneezes, or speaks, tiny fluid droplets containing the virus are expelled. If these are inhaled by others, the virus may establish itself in their noses and airways.

Colds can also be passed through direct contact. If a person with a cold touches his runny nose or watery eyes, then shakes hands with another person, the virus is transferred to the uninfected person. When the uninfected person touches his mouth, nose, or eyes, the virus is transported to an environment where it can reproduce and produce symptoms of illness.

Finally, cold viruses can be spread through inanimate objects such as doorknobs, telephones, or toys that become contaminated with the virus. This is a common method of viral transmission in childcare centers. When a child with a cold touches his runny nose, then plays with a toy, the virus may be transferred to the toy. When another child plays with the toy a short time later, he may pick up the virus on his hands. When the second child touches his contaminated hands to his eyes, nose, or mouth the virus is once again in an environment conducive to replication.

Once acquired, the cold virus attaches itself to the mucosal lining of the nasal passages and sinuses. This causes the infected cells to release a chemical called histamine. Histamine increases blood flow to the infected cells, causing swelling, congestion, and increased mucus production. One to three days following infection, the affected individual begins to experience cold symptoms.

The first cold symptoms are sore throat, runny nose, and sneezing. The initial discharge from the nose is clear and thin. Later it changes to a thick yellow or greenish discharge. Most adults do not develop a fever when they contract a cold. Young children may develop fevers to 102°F (38.9°C).

Along with a runny nose and fever, symptoms of a cold include coughing, sneezing, nasal congestion, headache, myalgias (muscle aches), chills, sore throat, hoarseness, watery eyes, fatigue, and loss of appetite. The cough that accompanies a cold is usually intermittent and nonproductive (dry).

Most people begin to feel better four to five days after cold symptoms become noticeable. All symptoms are generally gone within ten days, except for a dry cough that may linger for up to three weeks.

Colds increase susceptibility to bacterial infections such as strep throat, middle ear infections, and sinus infections. Individuals with symptoms that do not begin to improve within a week; or those with chest pain, persistent fever (fever for longer than a few days), difficulty breathing, productive cough, skin rash, swollen glands, or whitish spots on the tonsils or throat should consult a health care practitioner. The health care practitioner will determine if these patients have acquired secondary bacterial infections that require treatment with antibiotics.

People who have emphysema, chronic pulmonary disease, diabetes, or a weakened immune system—either from diseases such as AIDS or leukemia, or as the result of immunosuppressive medications (corticosteroids, chemotherapy drugs)—should consult a health care practitioner when they experience cold symptoms. Patients with these chronic health problems are at greater risk for secondary infections.