Stiffness and pain in hand:
The initial sign of arthritis is pain, stiffness, and tenderness. As you try to grip, pinch or clasp, you will feel the tenderness or pain in the base of your thumb. Simple things like turning the doorknob, twisting the key, etc. can cause lingering pain. However, severe pain doesn't mean that arthritis is also severe.
Weakness and decreased range of motion:
Because of the pain, eventually, the joints may weaken and lose their range of motion. It will worsen when you do actions like pinching or clasping something. Basic activities like opening a bottle, holding something, buttoning up, etc., will become difficult. In case of severe arthritis, the tasks that were simple earlier will be difficult or impossible without assistance.