Lung and Respiratory System Infectious Diseases Influenza, Colds, flus and other respiratory illnesses are more common in colder months. People are indoors more often, allowing viruses to pass more easily from one person to another. And the cold, dry air may weaken resistance.

If you’re coughing and sneezing this winter, how do you know if you have a cold or something more serious? Do you need antibiotics? Are you contagious? 

Michael Albert, M.D., Norman Dy, M.D., M.B.A., and Scott Feeser, M.D., at Johns Hopkins Community Physicians, suggest this quick guide to help diagnose and treat what’s ailing you.

Common Cold

What is it? Your nose and throat are infected. Also, maybe your ears.

How did I get it? Somebody coughed or sneezed near you, or you touched a contaminated surface, like a doorknob. More than 200 viruses can cause colds. The most common is the rhinovirus.

How I feel: Yucky. You probably have a runny nose, scratchy throat, low-grade fever, fatigue, chills and aches. And you probably are sneezing and coughing.

What should I do? You probably know that there’s no cure for the common cold. Decongestants, cough drops and antihistamines can help with symptoms. Rest and liquids may speed your recovery.

How long will it last? A few days to several weeks.

When can I go back to work? Most people are contagious for about a week, starting the day before they have symptoms. If you feel well enough to continue working, of if you go back within a day or two, wash your hands frequently and avoid close contact with others until you’re done coughing and sneezing.

How common is it? Very. Of all illnesses, common colds are blamed for the most days off work or school and the most visits to health care providers.

See a doctor if: Symptoms linger beyond a few days or get worse, or if new symptoms develop.


What is it? Your respiratory tract (mouth, nose, throat and lungs) is infected.

How did I get it? You got the flu from airborne droplets sneezed or coughed, or by touching contaminated surfaces. Flu viruses keep evolving, which is why flu shots, which are updated every year, are never fully effective.

How I feel: Terrible. You’re exhausted, you have a fever, your body aches, you’re sneezing and coughing, your throat is sore and you have a headache. You also might vomit or have diarrhea.

What should I do? Relieve symptoms with rest, fluids and medicines. In severe cases, antiviral medications like Tamiflu or Relenza may be prescribed to reduce the flu’s duration, severity and risk of complications. Antiviral medications usually have to be started within 48 hours of symptom onset to be helpful.

How long will it last? The worst of it — fever and aches — should be over in three to five days. The coughing and general tiredness can linger two weeks or more.

When can I go back to work? Wait at least five days after onset of symptoms and 24 hours after your fever breaks.

How common is it? Every year, between 5 and 20 percent of Americans get the flu, sending many to the hospital with severe complications.

See a doctor if: Symptoms get worse, you have new symptoms, or if you have a condition or situation that makes you vulnerable to flu complications.

Acute Bronchitis

What is it? Inflamed bronchi (the big tubes that bring air to the lungs), resulting in too much mucus.

How did I get it? Probably from a cold or flu virus — so getting a flu shot lowers your risk — or you might have inhaled bacteria. You’re particularly susceptible if you smoke or have allergies, sinusitis, or enlarged tonsils or adenoids.

How I feel: Like you can’t stop coughing. You probably started with a dry cough that soon became mucus-producing. You may also have aches and pains, chills, headache, runny nose, sore throat, shortness of breath, watery eyes and wheezing.

What should I do? Not much. It will clear up on its own — unless it progresses to pneumonia, which can be treated with antibiotics. Meanwhile, a humidifier, cough medicine and pain relievers can ease your symptoms.

How long will it last? About two weeks for most symptoms, though the cough can linger for a couple of months.

When can I go back to work? Bronchitis is not contagious once the initial viral phase subsides after a few days, so return to work when you feel strong enough.

How common is it? About 5 percent of adults and 6 percent of children are diagnosed with acute bronchitis in the U.S. each year.

See a doctor if: Symptoms don’t improve, or if they get worse.

Chronic Bronchitis

What is it? Inflamed bronchi (the big tubes that bring air to the lungs), resulting in overproduction of mucus. Bronchitis is considered chronic if you have a mucus-producing cough at least three months per year, two years in a row.

How did I get it? Probably from smoking, but irritants like air pollution may also be to blame.

How I feel: You have a persistent cough, plus chest discomfort and difficulty breathing.

What should I do? The goal of treatment is to reduce symptoms so you can breathe more easily. If you smoke, quitting is recommended. Oral or inhaled medications can open your airways. In severe cases, you might consider lung reduction surgery or a lung transplant.

How long will it last? Chronic bronchitis may ebb and flow, but it’s not going away.

When can I go back to work? Chronic bronchitis is not contagious, so work if you are able.

How common is it? About 9 million Americans each year are diagnosed with chronic bronchitis.

See a doctor if: You have a cough that lasts more than three weeks, produces bloody or discolored mucus, or is paired with a fever. Err on the side of caution and see a doctor even if you only suspect you have bronchitis — early treatment decreases the risk of lung damage.


What is it? Your lungs are infected, causing air sacs to fill with pus and other liquids.

How did I get it? Viruses are responsible for about one-third of cases. The rest are caused by bacteria or fungi that are inhaled, particularly by people weakened by surgery, illness, age or smoking.

How I feel: Symptom severity ranges from mild to life-threatening and can include confusion, fever, a cough that produces mucus, heavy sweating, shaking chills, lack of appetite, rapid breathing and pulse, shortness of breath that gets worse with activity, and stabbing pain in the chest that’s worse with coughing or deep breathing.

What should I do? If you have viral pneumonia, rest, eat well and drink plenty of fluids. Bacterial pneumonia can be treated with antibiotics. In both cases, medications can ease your fever and cough.

How long will it last? Most people respond well to treatment and recover in one to three weeks, but pneumonia can be very serious and even deadly.

When can I go back to work? If you have bacterial pneumonia, the risk of infecting others drops sharply two days after taking antibiotics. Viral pneumonia is less contagious, but avoid others if you have a fever. You’ll get better quicker if you don’t rush back to work until you’re ready.

How common is it? About 3 million people in the U.S. are diagnosed with pneumonia each year, and about 50,000 die.

See a doctor if: Your cough gets worse or doesn’t improve, you cough up pus, you have a persistent fever higher than 102 degrees, you have shaking chills, or breathing makes your chest hurt. Don’t delay seeing a doctor if you have underlying health conditions, such as heart or lung problems.

Whooping Cough

What is it? Also known as pertussis, whooping cough is a serious and very contagious bacterial infection that mainly affects infants and young children.

How did I get it? A bacterium called Bordetella pertussis, which is spread by coughing, sneezing and even breathing, causes whooping cough.

How I feel: It starts like a common cold, and progresses to include coughing spells that end with a whooping sound as you gulp for air. Other symptoms include fever, sneezing, runny nose and watery eyes.

What should I do? Your best bet is early treatment with antibiotics, which may reduce the infection and will make you less contagious. Stay warm, drink lots of fluids and limit exposure to things that make you cough, like smoke or dust.

How long will it last? Up to 10 weeks. It can lead to pneumonia and other complications.

When can I go back to work? Avoid contact with others until you have been treated with antibiotics for five days.

How common is it? Whooping cough is on the rise, because fewer children are getting vaccinations and then boosters every 10 years. In recent years, between 10,000 and 40,000 cases have been reported annually nationwide.

See a doctor if: You suspect you have whooping cough.