Upper airway cough syndrome (UACS), formerly known as postnasal drip syndrome, is characterized by upper airway and nasal irritation frequently caused by exposure to irritants, which include chemicals, dust, and allergens. UACS causes mucous to drip down the posterior naso- and oropharynx. The mucous can settle in the glottis (area above the windpipe) causing vocal cord or glottic stimulation resulting in a cough. UACS is the most common cause of chronic cough in adults.
There are no pathognomonic findings to establish the diagnosis of UACS. The diagnosis is determined by considering a combination of criteria. These include:
1. Symptoms: Symptoms can include a chronic cough, upper airway or nasal congestion, and rhinorrhea
2. Physical examination: Exam findings can include nasal erythema, inflammation and nasal or sinus congestion
3. Radiographic studies: Radiographic findings would include a normal chest x-ray and would aim to rule out other causes of a cough.
4. Response to specific therapy including nasal corticosteroids, oral decongestants, nasal antihistamines, and sedating or non-sedating oral antihistamines.
Upper airway cough syndrome medical expert witness specialties include allergy, otolaryngology, pulmonology, mold, radiology, and occupational medicine.