Viral Pharyngitis: This is the most common cause of sore throat in adults, often without systemic symptoms like fever or cough, especially in the elderly who may have a blunted immune response.

Gastroesophageal Reflux Disease (GERD): Can cause sore throat due to acid reflux, especially in the morning or after eating certain foods.
Allergic Rhinitis: Postnasal drip from allergies can irritate the throat, leading to soreness.
Dry Mouth (Xerostomia): Common in the elderly, especially those with decreased saliva production due to medications or other conditions, leading to throat discomfort.
Irritants: Exposure to smoke, pollution, or other environmental irritants can cause throat soreness.

Streptococcal Pharyngitis: Although less likely without fever, it's crucial to consider and rule out due to the potential for complications like rheumatic fever or glomerulonephritis.
Epiglottitis: A medical emergency that can present with severe sore throat, though typically accompanied by other symptoms like difficulty swallowing or shortness of breath.
Lemierre's Syndrome: A rare but serious condition following a sore throat, characterized by jugular vein thrombosis and septicemia, often due to Fusobacterium necrophorum.
Oral or Pharyngeal Cancer: Especially in elderly patients with risk factors like smoking or alcohol use, a persistent sore throat can be an early symptom.

Diphtheria: Although rare in vaccinated populations, it can cause a severe sore throat with a characteristic membrane.
Infectious Mononucleosis: Caused by Epstein-Barr virus, can present with sore throat, though typically accompanied by fever, fatigue, and lymphadenopathy.
Tuberculosis: Can cause a chronic sore throat, especially in immunocompromised individuals or those from endemic areas.
Sjögren's Syndrome: An autoimmune disorder that can cause dry mouth and throat, leading to soreness.