Recognizing Upper Airway Cough Syndrome: Key Clinical Clues

When a patient presents with persistent cough, what's at the top of your differential? If you answered upper airway cough syndrome (UACS), you're thinking like an expert. UACS—formerly known as post-nasal drip syndrome—is the most common cause of both subacute and chronic cough in primary care.

Despite its prevalence, UACS can be surprisingly easy to miss if clinicians do not ask the right questions. The key is recognizing the constellation of symptoms that point to upper airway pathology rather than lower respiratory or gastrointestinal causes, according to Vukiet Tran, MD, an emergency, family medicine, and long-term care physician.

Patient Care® spoke with Vukiet Tran, MD, an emergency, family medicine, and long-term care physician, during the 2025 FMX conference in Anaheim. In this segment, Dr Tran walks through the clinical clues that should immediately raise your suspicion for UACS, helping clinicians diagnose this common condition efficiently and accurately.

In this segment, Dr Tran covers:

• Why UACS should always be at the forefront of your differential
• The classic symptom pattern of post-nasal drip
• Positional and environmental triggers that point to UACS
• How timing of symptoms throughout the day aids diagnosis

The following transcript has been lightly edited for flow and style.

Patient Care: UACS is often described as one of the most common causes of chronic cough. What are the key clinical clues or patient characteristics that should make primary care clinicians suspect UACS?

Tran: UACS is the number one cause of subacute and chronic cough. It used to be called postnasal drip, and the symptoms are similar—nasal congestion, secretions, facial fullness, sore or itchy throat, and frequent throat clearing.

Patients often report that their cough worsens when lying down or sleeping because the secretions drip down the back of the throat. They may also cough more in response to cold air or while talking. Another clue is excessive phlegm in the morning as secretions accumulate overnight. When a patient presents with several of these symptoms, upper airway cough syndrome should be top of mind.

Dr Tran is the co-founder and president of the Canadian Physicians' Pension Plan, and an assistant professor in the Department of Family and Community Medicine at the University of Toronto.