Repetitive Strain Injury (RSI): This is a common condition that can affect anyone who performs repetitive activities with their hands, regardless of dominance. The non-dominant hand can still be subject to overuse, especially in activities that require bilateral involvement.

Osteoarthritis: A common condition that can affect any joint, including those in the hands. Pain in the non-dominant hand could be due to osteoarthritis, especially if the individual has a history of the condition or risk factors such as age or previous injuries.
Carpal Tunnel Syndrome: Although more commonly associated with the dominant hand due to overuse, carpal tunnel syndrome can occur in the non-dominant hand, especially if there are underlying anatomical or systemic conditions contributing to nerve compression.
Tendinitis: Inflammation of the tendons in the hand can cause pain and is not exclusive to the dominant hand. Activities that involve gripping or repetitive motion with the non-dominant hand can lead to tendinitis.

Acute Compartment Syndrome: A medical emergency that requires prompt diagnosis and treatment. It can occur in any hand, regardless of dominance, following trauma or intense activity, leading to increased pressure within the compartments of the hand.
Infections (e.g., Cellulitis, Abscess): Infections can occur in any part of the body, including the non-dominant hand, and require immediate medical attention to prevent serious complications.
Ganglion Cysts: While not typically life-threatening, ganglion cysts can cause significant pain and discomfort. They are a "do not miss" diagnosis because their treatment can significantly improve symptoms.

Gout: Although more commonly affecting the feet, gout can cause arthritis in the hands, leading to pain. It would be considered rare in the context of hand pain but should be considered, especially in individuals with a history of gout.
Sarcoidosis: A systemic disease that can cause inflammation in various parts of the body, including the hands. It is a rare cause of hand pain but should be considered in the differential diagnosis, especially if other systemic symptoms are present.
Ehlers-Danlos Syndrome: A group of disorders that affect connective tissues supporting the skin, bones, blood vessels, and many other organs and tissues. Defects in connective tissues cause the signs and symptoms of these conditions, which can include joint hypermobility and pain, making it a rare but possible diagnosis for hand pain.