Dry mouth and eyes are just a symptom and are not necessarily caused by disease factors.
Mild dry mouth and eyes may just be caused by a lack of moisture in the body. Significant dry mouth and eyes may be a manifestation of immune system diseases such as dry syndrome, toxic epidermolysis bullosa, systemic lupus erythematosus, rheumatoid arthritis and scleroderma, of which dry syndrome is the most common.
Dry syndrome is a chronic inflammatory autoimmune disease with systemic symptoms such as dry skin, fatigue, hypothermia and lethargy, in addition to dry eyes and dry mouth. Immunoserological tests may reveal a variety of positive antibodies such as antinuclear antibodies, anti-DNA antibodies, anti-ENA antibodies and rheumatoid factor.