Differential Diagnosis for Dry Cough, Ear Ache, and Congested Nostril

Single Most Likely Diagnosis

• Upper Respiratory Tract Infection (URTI): This is the most common cause of the symptoms described, including dry cough, ear ache due to Eustachian tube dysfunction, and congested nostril. URTIs are typically viral and self-limiting.

Other Likely Diagnoses

• Allergic Rhinitis: This condition can cause chronic or seasonal congestion, sneezing, and cough, along with ear discomfort due to Eustachian tube dysfunction. It's a common condition that could explain the symptoms if they are recurrent or related to specific allergens.
• Sinusitis: An inflammation or infection of the sinuses can cause nasal congestion, cough (especially at night), and ear pain due to the referred pain from the sinuses. It can be acute or chronic.
• Common Cold: Similar to URTI, the common cold is a viral infection that affects the upper respiratory system, leading to symptoms like cough, congestion, and sometimes ear ache.

Do Not Miss Diagnoses

• Pneumonia: Although less likely to present with ear ache, pneumonia can cause a dry cough and can lead to severe complications if not treated promptly. It's crucial to consider, especially in vulnerable populations like the elderly or those with compromised immune systems.
• Epiglottitis: This is a rare but potentially life-threatening condition that can cause severe sore throat, difficulty swallowing, and in some cases, ear pain due to referred pain. It requires immediate medical attention.
• Lung Cancer: In rare cases, a persistent cough could be a symptom of lung cancer, especially in smokers or those exposed to carcinogens. Although unlikely, it's a diagnosis that cannot be missed due to its severe implications.

Rare Diagnoses

• Tuberculosis (TB): TB can cause a chronic cough, among other symptoms. Although rare in many parts of the world, it's an important consideration, especially in individuals who have been exposed or have risk factors.
• Sarcoidosis: This is a condition that can affect multiple parts of the body, including the lungs, and can cause cough, among other symptoms. It's rare and would typically be considered after other diagnoses have been ruled out.
• Histoplasmosis: A fungal infection that can cause respiratory symptoms, including cough. It's more common in certain geographic areas and would be considered based on exposure history and other diagnostic clues.