Knuckle pads are benign fibrofatty subcutaneous pads located over the proximal interphalangeal (pip) joints that can be mistaken for arthritis. rarely they affect the dorsal aspect of the metacarpophalangeal (mcp) joints. clinically they are painless and often affect both hands in an asymmetrical pattern. [pmid:26672439]

Knuckle pads, also known as heloderma, meaning similar to the skin of the Gila monster lizard for which it is named, are circumscribed, keratotic, fibrous growths over the dorsa of the interphalangeal joints. They are described as well-defined, round, plaque-like, fibrous thickening that may develop at any age, and grow to be 10 to 15mm in diameter in the course of a few weeks or months, then go away over time. Knuckle pads are sometimes associated with Dupuytren's contracture and camptodactyly,: 595  and histologically, the lesions are fibromas.: 595  Knuckle pads are generally non-responsive to treatment, including corticosteroids, and tend to recur after surgery; however, there has been some effectiveness with intralesional fluorouracil..