In reply to Brum_climber:
I developed something similar in my right big tow joint, and at first thought it might be gout, then thought it was the start of rheumatoid arthritis, but then got it in my left big toe joint, and it's painful. Think I've developed Hallux Valgus and the cause of that is unclear. I haven't climbed for a while (for other reasons) but it's a bit sore most of the time and gets a bit worse when I run. It's obviously swollen on the joint and a bit red as well.
Did you actually injure your joint as it sounds you've just developed it as you don't mention an actual injury?