What is the likely cause of my chronic cough, weight loss, and new onset of throat phlegm, basal congestion, and hoarseness as an adult with no prior medical history?

Your Symptoms Suggest Upper Airway Cough Syndrome (UACS), Gastroesophageal Reflux Disease (GERD), or Laryngopharyngeal Reflux

Based on your constellation of symptoms—throat phlegm sensation, nasal congestion, and hoarseness—you most likely have upper airway cough syndrome (UACS) from rhinosinusitis, possibly combined with gastroesophageal reflux disease (GERD) or laryngopharyngeal reflux affecting your larynx. However, given your mention of chronic cough and weight loss in the expanded context, immediate evaluation is necessary to rule out serious underlying conditions before attributing symptoms to these common causes. 1, 2, 3

Immediate Concerns Requiring Urgent Evaluation

Weight loss combined with chronic cough is a red flag symptom that demands immediate investigation for serious underlying disease, including lung cancer, tuberculosis, or other systemic conditions. 2

• You need a chest X-ray immediately to exclude malignancy, infection, or other pulmonary pathology 1, 2
• Cough is the fourth most common presenting feature of lung cancer, and weight loss significantly elevates concern 4
• If chest X-ray is abnormal or symptoms persist despite treatment, proceed to chest CT scan and consider bronchoscopy 1

Most Likely Diagnoses for Your Symptom Complex

Upper Airway Cough Syndrome (UACS)

UACS is the single most common cause of chronic cough (accounting for 33-48% of cases) and can present with the exact symptoms you describe: throat phlegm sensation, nasal congestion, and cough—even without obvious nasal symptoms. 1, 2

• UACS results from rhinosinusitis, allergic rhinitis, or vasomotor rhinitis causing postnasal drip 1, 2
• This condition can be completely "silent" with minimal nasal symptoms, presenting only as throat clearing and cough 1
• The sensation of phlegm in your throat is classic for postnasal drip irritating the pharynx and larynx 4, 1

Gastroesophageal Reflux Disease (GERD) / Laryngopharyngeal Reflux

GERD is the third most common cause of chronic cough and can cause hoarseness through laryngopharyngeal reflux, where stomach acid irritates your larynx without causing typical heartburn. 1, 3

• Up to 75% of patients with GERD-related throat and voice symptoms have "silent GERD" without heartburn or regurgitation 3
• Laryngopharyngeal reflux specifically targets the upper airway, causing hoarseness, throat clearing, and the sensation of phlegm 3
• Laryngoscopy in reflux laryngitis shows red arytenoids and posterior laryngeal inflammation 3

Combined Diagnoses Are Common

Up to 25% of chronic cough patients have multiple simultaneous causes, and UACS combined with GERD is a frequent pairing. 1, 2

• All three major causes (UACS, asthma, GERD) must be considered in every patient regardless of which symptoms are most prominent 1
• Treatment often requires addressing multiple conditions simultaneously for resolution 2

Other Important Considerations

Pertussis Infection

Pertussis (whooping cough) should be considered, as it causes prolonged cough with hoarseness, throat symptoms, and can occur in adults despite childhood vaccination. 4, 5, 6

• In adults with pertussis, 91% have cough lasting an average of 54 days, 18% develop hoarseness, and 37% have pharyngeal symptoms 6
• Pertussis accounts for approximately 10% of chronic cough cases in some series 4
• Testing involves nasal swab PCR for Bordetella pertussis 5, 6

Laryngeal Hypersensitivity Syndrome

Chronic cough with hoarseness may indicate laryngeal hypersensitivity, where your larynx becomes hyperresponsive to normal stimuli. 7, 8, 9

• This manifests as persistent throat tickling, hoarse voice, and paradoxical vocal cord movement in 56% of chronic cough patients 9
• The hoarseness results from laryngeal motor dysfunction and vocal cord inflammation from repetitive coughing 7, 9
• Speech pathology intervention can be highly effective for refractory cases 7

Critical Diagnostic Approach

Essential History Elements to Clarify

• Medication review: Are you taking ACE inhibitors (blood pressure medications ending in "-pril")? These cause chronic cough in up to 16% of users 4, 2
• Smoking status: Current or former tobacco use is a major cause of chronic cough and increases risk of serious disease 4, 2
• Occupational/environmental exposures: Dust, chemicals, allergens at work or home 4, 2
• Geographic exposures: Travel to areas with tuberculosis or endemic fungal diseases 2
• Systemic symptoms: Fever, night sweats, hemoptysis (coughing blood) require immediate evaluation 2

Diagnostic Testing Sequence

1. Chest X-ray first to exclude serious pathology, especially given weight loss 1, 2
2. Empiric treatment trial for UACS with antihistamine/decongestant combination 4, 1
3. Consider GERD treatment trial with proton pump inhibitor, particularly if hoarseness is prominent 3
4. Spirometry and methacholine challenge if asthma suspected (though you don't describe wheezing) 4
5. Pertussis testing if cough is paroxysmal or contacts have similar illness 4, 6
6. Laryngoscopy if hoarseness persists beyond 2-3 weeks to visualize vocal cords 3, 5

Common Pitfalls to Avoid

• Do not assume the absence of heartburn rules out GERD—75% of reflux-related throat symptoms occur without typical GI symptoms 3
• Do not use cough character or timing to guide diagnosis—these features have no diagnostic value 1, 2
• Do not overlook weight loss—this symptom elevates concern for malignancy or systemic disease and requires thorough investigation 2
• Do not forget that multiple conditions often coexist—treating only one cause may leave symptoms partially unresolved 1, 2
• Do not delay evaluation if symptoms worsen or new concerning features develop (hemoptysis, fever, progressive weight loss) 2