I'm experiencing pain on the left side of my mouth and throat, along with a very dry mouth (xerostomia) and trouble swallowing (dysphagia), what could be causing these symptoms?

Unilateral Oral and Throat Pain with Xerostomia and Dysphagia

You need urgent evaluation to rule out serious structural causes—specifically infection, abscess, or malignancy—given the unilateral presentation, which is atypical for benign systemic causes of dry mouth. 1

Immediate Diagnostic Priorities

The unilateral nature of your symptoms is a critical red flag that distinguishes this from typical xerostomia presentations:

• Seek immediate medical attention if you have fever, difficulty breathing, progressive worsening, inability to swallow saliva, or severe pain, as these suggest peritonsillar abscess, deep neck infection, or obstructive process requiring urgent intervention 2
• Unilateral throat pain with dysphagia warrants direct visualization via clinical examination and likely endoscopy, as structural lesions (malignancy, abscess, stricture) commonly present this way 1, 2
• The combination of xerostomia and dysphagia can indicate Sjögren's syndrome, but this typically presents bilaterally, not unilaterally 3, 4

Differential Diagnosis Based on Your Presentation

Most Concerning (Require Urgent Evaluation)

• Oropharyngeal or esophageal malignancy: Unilateral pain is characteristic; dysphagia with weight loss or progressive symptoms mandates endoscopy 1, 2
• Peritonsillar or parapharyngeal abscess: Unilateral throat pain with dysphagia and potential trismus 2
• Salivary gland pathology: Unilateral submandibular or parotid gland obstruction, infection, or tumor 5, 3

Systemic Causes (Less Likely Given Unilateral Presentation)

• Medication-induced xerostomia: Anticholinergics, antihistamines, diuretics, psychotropic agents are the most common causes in the general population, but these cause bilateral symptoms 5, 6
• Sjögren's syndrome: Autoimmune condition causing severe xerostomia and dysphagia, but typically bilateral with dry eyes; can lead to dental caries and infections 3, 4
• Dehydration: Simple cause but presents bilaterally 5, 6

Recommended Evaluation Pathway

Step 1: Clinical Examination (Immediate)

• Direct visualization of oropharynx to assess for asymmetry, masses, tonsillar enlargement, abscess, or mucosal lesions 2
• Palpation of neck for lymphadenopathy or salivary gland enlargement 2
• Assessment for "alarm features": Progressive dysphagia, weight loss, age >55 years, or odynophagia (pain with swallowing) all increase malignancy risk and mandate endoscopy 7, 2

Step 2: Imaging Studies

For unexplained oropharyngeal dysphagia with unilateral symptoms:

• Fluoroscopy with biphasic esophagram is the preferred initial imaging, combining video fluoroscopy of the pharynx with static images of the entire esophagus, as distal lesions can cause referred pharyngeal pain 1, 7
• Modified barium swallow focuses on oral cavity, pharynx, and cervical esophagus to assess swallowing mechanics and aspiration risk 1, 7
• CT neck and chest may be indicated if structural abnormality is suspected on clinical exam, though not typically first-line for functional dysphagia 1

Step 3: Endoscopic Evaluation

• Esophagogastroduodenoscopy (EGD) is recommended when alarm features are present or if imaging suggests structural pathology 7, 2
• Allows direct visualization and biopsy of suspicious lesions, assessment for eosinophilic esophagitis, strictures, or malignancy 2

Symptomatic Management (While Awaiting Evaluation)

For Xerostomia

Mild symptoms:

• Increase hydration and limit caffeine intake 1
• Topical measures: Water sips, saliva substitutes, moisture-preserving mouth rinses, sugarless gum or lozenges 1, 5
• Saliva substitutes containing xylitol can reduce symptoms and dental complications 5

Moderate to severe symptoms:

• Systemic sialagogues: Pilocarpine or cevimeline to increase saliva flow 1, 6
• Consider prednisone 20-40 mg daily for 2-4 weeks if autoimmune etiology suspected, though this requires specialist guidance 1

For Dysphagia

• Dietary modifications: Avoid crunchy, spicy, acidic, or hot foods 1
• Chin-tuck posture during swallowing protects airways and prevents aspiration 7, 8
• Consider texture-modified diet using IDDSI framework if aspiration risk identified 7

Critical Pitfalls to Avoid

• Do not assume bilateral systemic causes (like medication-induced xerostomia or Sjögren's) when symptoms are unilateral—this delays diagnosis of structural lesions 1, 2
• Do not defer evaluation in patients with alarm features: Progressive dysphagia, weight loss, age >55, or odynophagia require prompt endoscopy 7, 2
• Recognize that distal esophageal or gastric cardia lesions can cause referred pain to the throat, so complete esophageal evaluation is essential 1
• Untreated severe xerostomia leads to dental caries and tooth loss—dental referral is essential for chronic cases 1
• Silent aspiration occurs in 55% of patients who aspirate—absence of cough does not exclude aspiration risk 1

Specialist Referrals

• Otolaryngology (ENT): For direct laryngoscopy and assessment of oropharyngeal pathology 2
• Gastroenterology: For EGD if structural esophageal pathology suspected 2
• Rheumatology: If Sjögren's syndrome suspected (bilateral dry mouth/eyes, positive autoantibodies) 1
• Speech-language pathology: For swallowing assessment and rehabilitation strategies 7, 2
• Dentistry: For preventive care if chronic xerostomia present 1, 5