A post-viral cough is a dry cough that persists for more than eight weeks after an upper respiratory infection caused by a virus. This can be irritating for the patient, especially because it may be difficult to treat by conventional means. For a severe cough, a medical evaluation can confirm that an underlying problem isn’t responsible, and the patient can be provided with some aggressive treatment options to see if the issue is resolved. Otherwise, the patient may have to allow the cough to run its course.
The precise causes of post-viral cough are not well understood. Researchers believe it may be related to the inflammation in the airway caused by the infection, which can excite cells and signaling pathways involved in the cough reflex. After the infection resolves, the patient may continue to cough. Initially the cough can include mucus and particulates as the airways clear. Later, it resolves into a dry, non-productive cough, indicating that the airways may be irritated but aren’t producing more mucus.
This cough can be worse in very dry environments, and may be triggered by talking or eating. Some patients with a post-viral cough find it helpful to drink plenty of fluids to stay hydrated. Cough lozenges are typically not effective, and measures like steam tents may offer limited comfort. If the cough becomes severe, the patient could have difficulty sleeping or exercising because of the throat irritation.
In the event a patient needs more aggressive treatment, the best option is usually a cough syrup that contains codeine. Opioids suppress the cough reflex and can keep a post-viral cough down while the airways recover. Such products need to be used with care and the patient may need to taper off at the end of the course of medication to prevent withdrawal symptoms. It’s also advisable not to save or share the medication, as this could result in inappropriate use that might be dangerous.
Cases of post-viral cough may be carefully evaluated to see if the patient has asthma, an airway obstruction, or another problem. These issues may have been masked before, or might have been triggered by the infection. Such workups can include imaging of the lungs, spirometry studies to assess airway function, and a careful patient interview to look for tell-tale symptoms that may not have been identified and addressed earlier. If the cause is something other than a virus, other treatments may be necessary to resolve the issue and help the patient recover from the cough.