If there is redness with a little bit of swelling on finger joints, that could be caused by Dermatomyositis which is systemic autoimmune disease. Immune system behaves abnormally, attacking healthy cells.
If it progresses, the muscles of the whole body get damaged and in some cases, the patients become unable to walk.
This disease tends to start with around finger joints.
Liver controls the amount of female hormone related to the widening of blood vessels. Chronic hepatitis causes imbalance of the female hormone, leading to the widening of blood vessels. By the increase of blood flow, under the thumb and little finger where a lot of capillaries gather become red.
There is a risk that it will progress to cirrhosis (of the liver). If you find the redness in these area, it is recommended to consult a gastroenterologist.