The Lingering Cough

Why do some coughs linger forever after a viral illness (and how do you know whether it’s something more)?

In this post, we’re going to talk about why coughs can linger after an upper respiratory infection, along with some of the possible causes and their signs/symptoms. Remember to check out these two posts too: cough 101 and things to try to help your child.

OMG with the coughing already

Coughing is frustrating. It can be the symptom that takes the longest to go away after an illness… and in fact, it can last so long it can make you wonder: “at what point should I be going back to the pediatrician?”

Why can it linger?

After an upper respiratory infection, it is common to have some residual inflammation that takes awhile to fade. From a physiology standpoint: coughing is a protective mechanism for the airway. The COUGH REFLEX becomes more sensitive after an inflammatory process; data shows an increased sensitivity of cough receptors (PMID: 10406052) and that sensitivity takes time to fade.

This “post-viral cough” is non-specific, usually dry, worse at night, and annoying. The good news? In the vast majority of cases it disappears within 2-4 weeks.

A good rule of thumb

Although post-viral inflammation is a common reason for an ongoing cough, there are many other causes we consider including back-to-back respiratory infections. The best way to tease these apart is to have your healthcare provider take a full history, and do a physical exam.

If cough symptoms last longer than 10-14 days without a break, or if a cough seems to be getting worse/has new associated symptoms, then it is time to touch base with your pediatrician.

But in many cases, if there is no clear underlying cause, they will likely tell you to watch and wait for a total of 2-4 weeks because we have studies that show that the likelihood of an underlying serious issue in a cough lasting less than 4 weeks after a viral infection is very low (PMID: 25501672)

But what if something more is going on?

This is certainly a possibility. That is part of why I recommend getting an assessment at the 10-14 day mark, and sooner if you notice any red flags (click here for a list).

Other reasons for a lingering cough

Some of the clues that we use to help determine if there is a cause for an ongoing cough are below. This is not a comprehensive list, but it may help give you some guidance as you think through what is happening in your child.

• Secondary infections

  • Can include things like pneumonia, sinus infections, ear infections, and more. These are just some of the symptoms we look at - and it is possible to have these infections without every symptom on the list. But in most cases if there is a secondary infection, new symptoms will develop. For example:

    • Pneumonia

      1. Sudden worsening of cough

      2. Change in sound of cough or extra sounds when breathing (such as wheezing)

      3. Pain (eg when taking a breath, when coughing, or chest pain)

      4. Difficulty breathing

      5. New fever or chills

      6. Overall seems unwell

      7. Easy fatigue

    • Ear infections

      • Fever

      • Ear pain or discharge

      • Poor sleep

    • Sinus infections

      • Headaches

      • Thick nasal discharge that is not improved or decreased (or improved then gets worse)

      • Sinus pressure

      • Tooth pain'

      • Loss of smell

      • Fever

      • Bad breath

• Asthma

  • Wheezing sound when breathing out

  • Shortness of breath; difficulty completing full sentences

  • Chest discomfort

  • Stopping while playing to catch their breath

  • Coughing spells that are worse with physical exertion, cold weather or at night

  • Signs of increased work of breathing (details here)

• Allergies

  • Accompanying symptoms: itchy eyes or throat, nasal congestion or runny nose, rashes, etc

  • A history of allergies either personally or in the family

  • A history of eczema or food allergies

  • Consistent pattern seasonally or with specific exposures, such as cats (or in certain rooms of the house)

  • A lack of symptoms of infection

• Habit cough (psychogenic cough, tic)

  • This tends to happen in children who are a little older (school age) and is sometimes triggered by a recent upper respiratory infection. As with other tics (such as blinking, throat clearing, etc) it can also be triggered by recent transitions or stress. Note: the child is not faking the cough.

  • Consistent pattern

  • Dry and can sound quite dramatic (honking, harsh or loud)

  • Only occurs when awake

  • May not occur when distracted

  • A lack of other signs of infection or allergy

  • May be associated with times of stress, such as transitioning to school

• Other causes

  • Depending on the history, other causes of an ongoing cough can include:

    • Reflux

    • Foreign body (such as aspiration)

    • Underlying health issues (such as CF)

    • Irritants in the environment (such as secondary smoke exposure or mold)

    • Anatomic or congenital issues

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Bottom line: it is never wrong to have your child assessed. Trust your spidey sense.

But pediatricians are often just as frustrated at parents about “non-specific cough” because we understand how frustrating it can be to not know how to help your child. Unfortunately - or fortunately - sometimes tincture of time is the best (and only) treatment.