What autoimmune disease causes dry eyes and dry mouth?

Sjögren's syndrome is the autoimmune disease that characteristically causes dry eyes and dry mouth.

The immune system mistakenly attacks moisture-producing glands, especially the lacrimal glands that make tears and the salivary glands that make saliva. This produces the condition's hallmark dryness, medically associated with keratoconjunctivitis sicca and reduced saliva flow.

The disease can also cause fatigue, joint pain, dry skin, swollen salivary glands, difficulty swallowing, and problems affecting the lungs, kidneys, nerves, or other organs. Some people have Sjögren's alongside another autoimmune disease such as rheumatoid arthritis or lupus, which can cause confusion in quiz questions.

The condition is named after Swedish ophthalmologist Henrik Sjögren, who described patients with dry eyes and arthritis in the early 20th century. “Sjögren's disease” is increasingly preferred in medical usage, but “Sjögren's syndrome” remains a widely accepted name for the same condition.