What Causes Hand Swelling?

Hand swelling may arise from various causes—both physiological and pathological. Physiological causes include excessive fluid intake in the evening, which can lead to water and sodium retention and result in hand swelling upon waking the next morning. Another common cause is inadequate warmth during nighttime sleep, exposing the hands to cold temperatures and triggering swelling. Pathological causes are more complex and may involve joint inflammation—for example, rheumatoid arthritis—whose symptoms (including swelling and pain) often worsen following cold exposure. Additionally, localized injury to the hand can also cause edema. Accurate identification of the underlying cause is essential to guide appropriate treatment.