Postinfectious Cough

Postinfectious cough is a cough that lingers for weeks or even months after an upper respiratory infection. This happens because of germs like viruses and bacteria. It’s also sometimes known as postviral cough or postviral cough syndrome.

Postinfectious cough is common and can happen at any age. It’s more likely to be a cause of chronic cough in adults than it is in children. Up to 1 in 4 adults who get an upper respiratory infection can develop it. And while it isn’t a dangerous condition, it can definitely be unpleasant.

Symptoms of postinfectious cough

A persistent or chronic cough is the key symptom of postinfectious cough. A persistent cough lasts three to eight weeks. A chronic cough lasts eight weeks or more.

This cough is usually:

• Not severe: You’re not coughing hard or having coughing fits.
• Nonproductive: It’s dry, meaning it doesn’t bring up mucus.
• Gradually weaker: It usually fades slowly over time.

Postinfectious cough causes

There are two main causes of postinfectious cough: bacteria and viruses.

Bacterial causes include:

• Chlamydia pneumoniae (which can cause pneumonia)
• Mycoplasma pneumoniae
• Whooping cough (postinfectious cough is much more common with this)

Viral causes include:

• Adenoviruses
• Coronaviruses, including the ones that cause the common cold and COVID-19
• Parainfluenza
• RSV

Postinfectious cough isn’t contagious. But it’s important to see a healthcare provider so they can rule out a lingering infection when they diagnose your cough. That way, you can be sure you won’t pass an infection to anyone who’s vulnerable.

Why it happens

Experts don’t fully understand why postinfectious cough develops. But they suspect a few reasons:

• Inflammation: Your immune response may leave behind inflammation that takes time to heal.
• Mucus buildup: Infections increase mucus and make it harder to clear, which can irritate airways even after you’re better.
• Nerve sensitivity: Some infections may hypersensitize cough reflex nerves, making you cough more easily.

How doctors diagnose postinfectious cough

To diagnose postinfectious cough, your provider will:

• Do a physical exam and listen to your breathing
• Ask about your symptoms and any recent upper respiratory infections
• Recommend and run tests if needed
• Rule out more serious causes of chronic cough

If you have a history of multiple rounds of pneumonia or smoking, be sure to tell your provider about those, too. Your provider will need to know about that to diagnose you properly.

Tests that are used

Your provider might use the following tests to diagnose postinfectious cough:

• Blood tests
• Chest X-ray or CT scan
• Pulmonary function tests
• Throat culture test

How is postinfectious cough treated?

Postinfectious cough doesn’t need treatment. Prescription medicines, like antibiotics, won’t help it. This condition gets better on its own. But make sure you get a diagnosis before waiting it out.

When should I see my healthcare provider?

You should see your provider if you have a cough that lasts more than a couple weeks after other infection symptoms clear up. And you should ask for a follow-up appointment if you still have your cough eight weeks after seeing your provider.

You should also see your provider as soon as possible if you have a persistent cough with any red-flag symptoms. Most of them are signs of something severe that needs care quickly.

Red flag symptoms include:

• Coughing blood
• Hoarseness
• Other symptoms throughout your body, like fever, unexplained weight loss, or foot/leg swelling with weight gain
• Severe breathing difficulty, especially when resting or at night
• Trouble swallowing
• Vomiting

What can I expect if I have a postinfectious cough?

Postinfectious cough can be unpleasant and annoying. But it isn’t dangerous. The outlook for it is excellent.

This condition should go away within several weeks. But don’t wait too long to get that diagnosis in the first place. And see your provider again if you still have the cough eight weeks after your diagnosis.

Is there anything I can do to feel better?

Home cough remedies may help you cope with postinfectious cough. Cough drops could also help, but don’t overuse them. That could make your cough worse.

You might feel tempted to reach for cough syrup or other over-the-counter (OTC) cough medicines if you have postinfectious cough. But those products won’t make this condition go away any faster. And they could cause other unwanted effects.

Your healthcare provider can offer guidance on what else you can do to ease your symptoms.

Can postviral cough turn into pneumonia?

No. Postinfectious cough can’t turn into pneumonia. This condition only happens after the infection is gone.

But similar conditions that cause chronic cough can lead to pneumonia. That’s why you should see a provider if you have a lingering cough for more than a couple weeks.