Persistent Sore Throat

A persistent sore throat – pharyngeal pain, discomfort, or irritation lasting more than two to three weeks – that does not resolve with standard treatment or without an identifiable acute infectious cause warrants careful clinical evaluation.

Transient sore throat is one of the most common presenting complaints in primary care, the large majority of cases being caused by viral upper respiratory tract infections and resolving spontaneously within one to two weeks. Bacterial pharyngitis (most commonly Streptococcus pyogenes) resolves with antibiotic therapy.

A persistent sore throat – defined here as throat discomfort lasting beyond two to three weeks, or recurrent episodes with incomplete resolution – has a broader differential diagnosis that includes structural, inflammatory, reflux-related, and neoplastic causes. Because head and neck malignancies, particularly oropharyngeal and hypopharyngeal cancers, can present with persistent sore throat as the predominant or only early symptom, this symptom should not be indefinitely attributed to minor causes without assessment.

Infectious causes

• Acute viral or bacterial pharyngitis (most common; usually self-limiting)
• Infectious mononucleosis (Epstein-Barr virus): Can cause severe, prolonged pharyngitis with marked tonsillar enlargement and systemic symptoms
• Peritonsillar abscess: Deep infection causing severe unilateral throat pain, muffled voice, and trismus
• Chronic or recurrent tonsillitis
  
  
  

Inflammatory and non-infectious causes

• Laryngopharyngeal reflux (LPR): Retrograde flow of gastric contents reaching the larynx and pharynx causes chronic mucosal irritation, producing a persistent sore throat, globus sensation, and chronic throat clearing — often without classic heartburn
• Allergy and post-nasal drip: Mucosal irritation from chronic post-nasal drainage
• Chronic pharyngitis: Persistent mucosal inflammation caused by prolonged exposure to tobacco smoke, alcohol, chemical fumes, or dry air
• Sjögren's syndrome: Autoimmune condition producing salivary and lacrimal gland dysfunction; oral dryness increases mucosal susceptibility to irritation and discomfort
• Malignant causes
• Oropharyngeal cancer: Tonsil cancer and tongue base cancer frequently present with persistent unilateral sore throat, which may be associated with referred ear pain; because these tumors are not directly visible on routine oral examination, the symptom may be attributed to other causes until the tumor is detected by endoscopy
• Hypopharyngeal cancer: Tumors of the pyriform sinus, posterior pharyngeal wall, or post-cricoid region may present with a persistent foreign-body sensation or throat discomfort
• Laryngeal cancer (supraglottic): Tumors above the vocal cords may produce throat discomfort, pain on swallowing, or referred ear pain before causing hoarseness
  
  
  

Risk factors for malignant causes

• Tobacco use (current or former)
• Heavy alcohol consumption
• HPV infection (associated with oropharyngeal cancer)
• Age over 40
• Prior head and neck cancer or radiation to the head and neck

See a physician if:

• Sore throat persists for more than two weeks without improvement
• Sore throat does not resolve with an appropriate course of antibiotics
• Sore throat is unilateral (one-sided), as asymmetric pharyngeal pain is more suggestive of a structural cause
• Sore throat is accompanied by difficulty swallowing, hoarseness, or unexplained weight loss
• A neck lump is associated with throat discomfort
• Ear pain on the same side as a persistent sore throat without an ear problem is present (referred otalgia)
  
  

Seek urgent or emergency evaluation if:

• Throat pain is severe and accompanied by difficulty breathing, stridor, or inability to swallow saliva
• High fever with rapid neck swelling and trismus suggests a deep space infection (peritonsillar or retropharyngeal abscess)

A persistent sore throat in an adult – particularly with unilateral symptoms, associated neck lump, or risk factors including tobacco and alcohol use – requires examination by an otolaryngologist including endoscopic assessment of the pharynx and larynx.