One potential cause for a painful swollen area on the wrist or back of the hand is a ganglion cyst. Essentially, a ganglion cyst is a small pocket over a joint or tendon (tissue that connects muscle to bone) where fluid has built up. Most often, this happens on the back of the wrist, although it can also happen on the palm side of the wrist.
Since it is fluid-filled, the lump will soft and squishable but you won’t be able to move it around. It may even change in size (often increasing after activity), or disappear completely for a period of time. There are frequently no symptoms besides the presence of the lump.
However, some cases can be very painful and you may even notice a loss of hand strength or hand control if the cyst lies over the top of a tendon or nerve. The exact cause of a ganglion cyst is unknown; it can present after the trauma but most often it will appear with no obvious cause. This makes prevention difficult.
What can you do about it?
Many ganglion cysts will disappear on their own with time, although some don’t and often they can return. A physical therapist is a great resource to seek out if you believe you may have a ganglion cyst that is painful or limiting your function.
They will be able to rule out any other causes for your wrist pain, as well as assist you in decreasing your pain and improving your wrist function. The majority of cases will be resolved with this approach, however, if it is unsuccessful after some time your physical therapist can refer you to a surgeon who may aspirate (drain) the cyst with a needle or do a surgical removal.
*It should be noted that the traditional treatment approach of hitting the wrist with a heavy textbook is not supported by research and is not recommended by medical professionals, as it may cause further damage to the surrounding structures.
Nahra, M. E., & Bucchieri, J. S. (2004). Ganglion cysts and other tumour-related conditions of the hand and wrist. Hand Clinics, 20(3), 249–260. doi: 10.1016/j.hcl.2004.03.015
Suen, M., Fung, B., & Lung, C. P. (2013). Treatment of Ganglion Cysts. ISRN Orthopedics, 1–7. https://doi.org/10.1155/2013/940615