Fat fingers can result from a variety of causes. Fingers store fat just as any location on the body and may gain fat in ordinary ways. Another cause of fat fingers may be water retention, as explained by the Better Health Channel. Fluid regularly seeps into body tissues from the blood, but the lymphatic system generally removes it, placing it back in the blood stream.
There are two types of fluid retention, according to the Better Health Channel. When swelling occurs everywhere on the body, the retention is known as generalised oedema. When only one area of the body is affected, such as the fingers, it is known as localised oedema.
There are many causes for water retention. They can be a result of the body's reaction to hot weather, a high salt intake or even certain hormones associated with menstrual cycles, as explained by the Washington Post. Even though water retention may result in nothing, it can be an indication of serious disease, such as heart, kidney or liver disease. For this reason, it is recommended to consult a doctor if it occurs.
According to HealthTap, other causes for fat or swollen fingers include anasarca, angioedema, osteoarthritis, rheumatoid arthritis and chronic overuse syndrome. HealthTap recommends getting examined by a doctor to determine if the fingers need specific treatments.