There is some evidence that infection with an A-type retrovirus may be present. Symptoms of the sicca syndrome may develop either slowly and insidiously or rapidly. When the onset is rapid, episodic parotitis may accompany the disease. Keratoconjunctivitis causes a sensation of a foreign body in the eyes, a variable accumulation of thick secretions near the inner canthus of the eyelids, decreased tearing, redness, and photophobia. A film of thickened secretions over the cornea may interfere with vision, and excessive dryness may cause corneal ulceration and serious loss of vision.
Salivary insufficiency leads to difficulty in chewing.
Swallowing food may require frequent ingestion of water or other liquids while eating. Severe dental caries and breakdown of dental restorations may develop. Less commonly, dryness of the upper respiratory tract and tracheobronchial tree may cause epistaxis, hoarseness, bronchitis, or pneumonia. Parotid gland enlargement occurs in about one half of patients. The presence of keratoconjunctivitis sicca is reliably established by slit-lamp examination by an ophthalmologist after the cornea has been stained with rose bengal dye.