Which condition can cause xerostomia?

• A. Sjogren's syndrome
• B. Diabetes mellitus
• C. Hyperthyroidism
• D. Osteoarthritis

Answer: (A)

Xerostomia happens when saliva production drops due to impaired salivary gland function. Sjogren's syndrome is an autoimmune disease that specifically targets the moisture-producing glands, especially the salivary and lacrimal glands, leading to a persistent dry mouth (xerostomia) and dry eyes. This direct glandular attack makes Sjogren's the best answer because it explains a primary, mechanism-based cause of reduced saliva.

Diabetes mellitus can cause dry mouth in the context of dehydration or high blood sugar, but it isn’t a primary gland disease. Hyperthyroidism and osteoarthritis don’t typically cause xerostomia through salivary gland dysfunction, so they’re not the classic culprits.