ZocdocAnswersWhy is my thumb swollen?

Question

Why is my thumb swollen?

It's been a couple weeks now, and my thumb is still swollen! On the side of my thumb there's a round bump on it, press around the bump and it's a little painful, press on the bump and it feels like a knife. But it feels like the bump is hollow. What could it be?? Theres no marks on it, such as bite marks. It's just a red round lump on the side of my thumb.

Answer

A painful bump on the thumb can have multiple causes, some benign and others more serious, therefore I recommend that you see your doctor for a formal evaluation. If the painful bump is overlying a joint it could be due to a bony, ligamentous or tendinous abnormality. Prior injury to the thumb either by overextending, crushing or compressing the joint could result in injury to these structures. Arthritis of the joint, most commonly osteoarthritis, can lead to chronic irritation though is generally not very tender to touch. Inflammation of the joint capsule due to chronic overuse or injury may lead to swelling and tenderness. Chronic fracture of one of the bones of the thumb may also lead to swelling, inflammation and pain, however, the symptoms are usually severe enough in these cases to preclude use of the digit. Soft tissue abnormalities, such as chronic infection can lead, for example a felon, which is a local infection of the pad of the digit is another commonly seen cause. Finally, growths such as a cyst can rarely present in the digits and cause pain with movement and irritation to the site can lead to inflammation and pain over time. Please see your doctor for evaluation of your symptoms, which may require further testing and treatment. Generally, rest and icing can help alleviate symptoms until a definitive source is elucidated. Try to avoid vigorous use of the digit until formally evaluated by a healthcare professional.

This answer is for general informational purposes only and is not a substitute for professional medical advice.

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