Upper Respiratory Infections

Upper Respiratory Infections, Viruses, Bacteria

One of the most common reasons for visiting a doctor is an upper respiratory infection (URI), also known as the common cold. These infections cause primarily nose, throat, head and ear symptoms. Let's face it, they are miserable. On average, children get 4 to 6 colds per year and adults get about 3 a year. It is important to understand the causes of upper respiratory infections and the appropriate treatments (but, if you just want to know when to see the doctor, skip to the end).


Viruses are very small packets of genetic material.  By some criteria, they may not even be considered living things.  They do not multiply on their own. They attach to tissue such as the nose, throat or stomach and get inside our cells.  Once inside, our own cell's machinery is tricked into making lots of copies of the virus. This process kills the cell. The virus copies then invade the surrounding cells.  It doesn't take much exposure to to get this process rolling. During a URI, billions of viruses are shed from the nose in each sneeze or blow of the nose.  They get on your hands. They get on anything that your mouth and nose touch. Drugs do not kill viruses, because they are not really alive. Fortunately, we have a sophisticated defense system...

The Immune System

The immune system gets activated when a virus invades your body. In fact, it is your immune system that makes you feel sick. The only way to defeat a virus is to destroy the cells that contain the virus.  During the first 4 to 5 days of a URI, the immune system destroys the cells that line the throat and the nose. This causes sore throat, nose irritation, sinus inflammation, sneezing, congestion, fatigue, body aches and sometimes fever.  The battle leaves behind many dead nose cells and immune cells (white blood cells).  To get this debris off of the battlefield, our noses make mucous. This watery substance washes the dead cells out of the nose. At the peak of the battle, there are a lot of dead cells to clear.  This makes the mucous very thick and ugly. The symptoms can sometimes be pretty bad.

The Natural History of a URI

The natural history of a URI is as follows:

Days 1-3 - Possible fever, sore throat, fatigue, body aches. Possible loss of voice. Nose congestion and cough begin.

Days 3-5 - Nose congestion worsens. Sinus pressure develops in the cheeks and the forehead. Mucous thickens. Sore throat fades.  Fever breaks. Cough usually worsens.

Days 5-10 - The mucous thins out. Sinus pressure decreases. Symptoms gradually fade.

Drugs do not alter this chain of events.

Treatments for viral URI's

Treatments for viral URI's are therefore aimed at helping the symptoms and decreasing the spread of the germs.

1. Rest. The immune system uses up a lot of energy.

2. Hydration:  drink extra water, get extra humidity (steamy showers, humidifiers). This keeps the mucous from getting too thick.

3. Wash your hands. Do not share food, cups, utensils, straws. Do not eat from a common plate with other people. No kissing.

4. Careful use of Acetaminophen (Tylenol) or Ibuprofen (Motrin, Advil) for pain (read the instructions).

5. Decongestants are no longer recommended (they raise blood pressure, pulse and the risk of heart attack and stroke).

About 90 % of the time, nothing else happens. 

However, sometimes this whole process can allow your body's bacteria to get trapped in the mucous filled sinuses, ears and airways. This can lead to a second infection from bacteria.

If symptoms worsen or persist beyond the first week, then it is time to see the doctor.


Bacteria are true, living cells. They can multiply on their own in the right environment. They come in 2 basic forms: the kind that live in our bodies all the time, and the kind we "catch" from other people. The bacteria that live in our bodies may cause second infections after colds, or the so-called "sinus infections". The other kind (the kind that we catch) may cause infections limited to the throat or lungs, but they usually spare the nose. In fact, that is the key. Viral URI's (and the sinus infections that occasionally follow them) cause nose problems. Bacterial throat and bronchial infections usually do not.

Only about 10% of colds are followed by bacterial sinus infections. Once your own bacteria gets trapped in a sinus during the initial cold, it takes about a week or more for them to overgrow and cause a second infection.

The Natural History of Bacterial Sinus Infections

The natural history of bacterial sinus infections and ear infections are as follows:

Days 1-7 - Typical URI symptoms as above (from virus).

Days 7-10 - Symptoms of URI fade. New symptoms may begin or seem to "rev up" again (fever, pain in the cheeks or ears, increase in thick mucous, and cough).

Days 10 - ? - Symptoms persist or worsen. They may fade naturally over a few weeks.

** Remember, after the first URI symptom, it takes about one week or more for bacterial sinus infections to even cause problems! 

Because bacteria are true living things that live outside of our cells and multiply on their own, drugs can be used to kill them.

Antibiotics are drugs that either stop bacteria from multiplying or destroy their protective outer coats.  As stated above, they do not kill viruses . They may become useful if the symptoms of the URI worsen or persist after the first week. Until then, they should not be used.

Please note that some bacteria are "caught" like viruses. These cause infections like strep throat and some forms of bronchitis or pneumonia. They usually do not involve the nose. If things do not seem to fit the above description, then see the doctor.

Why don't we just give everyone antibiotics during their cold (ie, during the first 7 days)? As mentioned above, viruses cause colds. Antibiotics don't kill them. Only your immune system kills them. A lot of people get confused when a doctor, rushed for time, gives an antibiotic script to someone with a cold. They start the antibiotic on day 4 or 5 (the peak days), then the cold improves. Wow. The antibiotic seemed to make the cold better. However, colds start getting better anyway after the fifth day. There's an old joke about colds, "If you take an antibiotic, you'll be better in about 7 days, but without the antibiotic, it'll take a whole week!"

Antibiotics are dangerous. They kill weak bacteria much better than they kill strong bacteria. We have a lot of bacteria in our body. Every time we poison them with antibiotics, we kill the week and leave the strong.  The strong bacteria then multiply. We become populated with strong bacteria that cannot be killed by the antibiotic. This is called resistance .

Resistant bacteria are killing us!  The news media creates a scare every now and then by reporting on the latest death due to MRSA (methicillin resistant staph aureus). This common bacteria is resistant to multiple antibiotics and causes a lot of disease. Others are less popular in the media but just as dangerous. We now have VRE (vancomycin resistant enterococcus), Clostridium difficile ("c. diff") and others. Researchers are worried that one day, antibiotics will be useless.

We understand that colds are messy. We all get them. They make us feel terrible. They make us miss work and school. But they get better. Antibiotics are rarely needed, and then for infections that come after the cold.

So, the next time that you or your child has a respiratory infection and the doctor says that antibiotics are not appropriate, please realize that the doctor is trying to protect you. We do use antibiotics when URI symptoms change or worsen after the first week or so. Before this time, you're likely better off without them.

What about fever?

Sometimes the body's thermostat, called the hypothalamus, resets the body's temperature to a higher level when a person has an infection.  This may help the infection fighting cells (white blood cells) work more efficiently.  Fever is a sign that the body is fighting an infection.  The fever is not the illness.  When the temperature is going up, we feel chilled.  When the temperature goes back down, we feel warm and may even break a sweat. 

Using Acetaminophen (Tylenol) or Ibuprofen (Motrin, Advil) may help a sick person feel better when fever is present.  In fact, that is the only reason to use these medications when ill.  Artificially lowering the temperature does not help the body fight illness. Beware of "fever phobia".

A child may generate very high temperatures even with common viruses like colds or stomach viruses.  We should focus on how a person is actually feeling, rather than the number on the thermometer. An exception is in infants under 3 months of age.  Infants under 3 months old should always be evaluated emergently if they have a fever because it may be an indicator of a serious bacterial infection that they acquired during birth. 

When do you need to see the doctor?  

See the doctor when:

1. Your URI symptoms change or worsen after the first week.

2. The symptoms are severe (just because you may not need antibiotics, does not mean that you may not need other kinds of treatment, like breathing treatments for asthma).

3. The symptoms are in the throat and/or chest, but not the nose.

4. You are not sure.

Signs of Emergencies

(Time to call us or get seen right away)

1. Mental status changes, confusion, difficult to arouse.

2. High pitched scream in an infant.

3. Difficulty in breathing (not just congestion in the nose).

4. Fever with rash (it's always a good idea to at least call us or get seen).

5. Inability to hold down any fluids for over 6 hours (even sips).

6. Extreme pain.