Arthritis causes cysts to form on the fingers in two ways: by causing bone degeneration at the ends of finger joints or through metabolic change in cells that produce hyaluronic acid, according to the American Association of Family Physicians. The cysts are known as mucous or ganglion cysts and form either at the joints or at the base of the fingernail.
Mucous cysts typically develop in conjunction with the symptoms of osteoarthritis, states WebMD. They most commonly affect middle-aged and elderly persons and appear twice as often in women as they do in men.
The cysts feel firm and do not move easily under the skin, claims WebMD. Mucous cysts are painful and limit a person's range of motion, but they can break open under pressure. Open cysts have a high risk of infection, and patients are advised to resist the urge to open a cyst on purpose.
Treatments for mucous cysts involve injecting or expressing the cyst and surgical removal, notes the American Association of Family Physicians. Cysts are injected with a steroid, such as hydrocortisone, to reduce the swelling and inflammation. Alternatively, the fluid contents of the cyst are expressed using a needle to temporarily reduce the size of the cyst. If these methods prove unsuccessful, the cyst is frozen and surgically removed.
Mucous cysts frequently reappear when removed surgically, warns the American Association of Family Physicians. Additional steps can reduce the likelihood of a recurrent cyst, including removing segments of bone growing alongside the cyst and limiting the number of sutures to allow the wound to close on its own.