I’d like to raise your awareness to another possibility – Raynaud’s and thoracic outlet syndrome. Raynaud’s is a sensitivity to cold which causes poor blood circulation to the fingers and causes them to turn red and blue. About half of Raynaud’s cases are simple, meaning they are not caused by any underlying factors – you simply need to stay warm to avoid the symptoms. However, about half of Reynaud’s cases are caused by underlying conditions such as lupus or thoracic outlet syndrome (TOS). TOS is a group of symptoms caused by the fact that sometimes a person’s rib or collarbone structure causes crowding in the chest area and presses on arteries or nerves, causing a lack of blood flow to the fingers. Someone I know, in her late teens, suddenly in the wintertime developed several swollen fingers that looked arthritic. The family doctor said it was Raynauds. However, I did some internet research and saw info about TOS that seemed applicable in her case. In arterial TOS for example, the particular fingers that tend to swell were the same ones that swelled in her case. The swelling disappeared when the weather warmed up but then returned the next autumn. At that point she underwent some tests that measure finger temperatures after hands are immersed in ice cold water several minutes apart over a period of time. Her fingers took longer than normal to return to regular temperatures. Another test was a measure of blood flow to her hands. She fortunately has a mild case in which she is advised to 1) exercise to help increase blood flow; 2)try to gain a little weight to increase her body warmth (she is thin); 3)wear wool gloves, wool socks, and a hat and dress warmly enough when the whether gets cool or cold. Some people take a non-steroidal anti-inflammatory for this but she didn’t need to. In extreme cases surgery is performed to break the bone that is compressing everything in the chest and create more room.
You may want to ask your doctor if this is a possibility in your case.