Differential Diagnosis for Clear Watery Discharge from the Nose
- Single Most Likely Diagnosis
- Allergic rhinitis: This is the most common cause of clear watery discharge from the nose, often associated with other symptoms like sneezing, itching, and nasal congestion. The discharge is typically clear and watery due to the release of histamine and other chemical mediators from mast cells in the nasal mucosa.
- Other Likely Diagnoses
- Viral upper respiratory tract infection (common cold): This can cause a clear watery discharge, especially in the initial stages of the infection. The discharge may later become thicker and more purulent as the infection progresses.
- Vasomotor rhinitis: This non-allergic condition is characterized by an overactive nasal response to various stimuli, leading to clear watery discharge, often without other symptoms like itching or sneezing.
- Sinusitis: Although the discharge in sinusitis is often purulent, in the early stages or in cases of serous sinusitis, the discharge can be clear and watery.
- Do Not Miss Diagnoses
- Cerebrospinal fluid (CSF) leak: Although rare, a clear watery discharge that is high in volume and persists over time could indicate a CSF leak, which is a serious condition requiring immediate medical attention. Testing for beta-2 transferrin can help diagnose a CSF leak.
- Skull base tumor: Tumors in the skull base area can cause clear watery discharge due to the obstruction of normal nasal and sinus pathways or erosion into the CSF space.
- Rare Diagnoses
- Nasal foreign body: In children, a foreign body in the nose can cause a unilateral clear watery discharge due to irritation and obstruction.
- Fungal infections: Certain fungal infections, like allergic fungal rhinitis, can cause clear watery discharge, although this is less common and often associated with other symptoms like nasal polyps and thick, eosinophilic mucin.
- Granulomatosis with polyangiitis (formerly known as Wegener's granulomatosis): This rare autoimmune disorder can cause a variety of nasal and sinus symptoms, including clear watery discharge, due to granulomatous inflammation and vasculitis.