Other possible causes include:
- Osteoarthritis: The most common cause. The bumps are typically hard, bony, and may be accompanied by stiffness or aching.
- Psoriatic arthritis: Can affect the joints near the nails, especially if the person has psoriasis or nail changes.
- Gout: Can occasionally cause hard deposits (tophi) around finger joints, though this is less common.
- Digital mucous cyst: Usually appears as a single firm lump near the nail rather than multiple hard bumps.
The reason they appear on more fingers over time depends on the cause. With osteoarthritis, it’s not that the bumps are spreading from one finger to another; rather, multiple joints gradually undergo similar wear-and-tear changes, influenced by age, genetics, prior joint injuries, and repeated use.
A healthcare professional can often identify the cause by examining the hands. Sometimes an X-ray is used to confirm osteoarthritis or look for other joint conditions.
She should seek prompt medical evaluation if the bumps are associated with:
- Rapid swelling, redness, and warmth.
- Severe pain or fever.
- A sudden inability to move the finger after an injury.
- Drainage from the bump or signs of infection.
If you can upload a clear photo of her hands (especially the affected joints near the nails), I can help identify which cause seems most likely, though I can’t diagnose it from an image alone.
