Pain Near Fifth Metacarpal

After the second day of a Red Rock trip that featured six consecutive days of mid-intensity, high-mileage climbing, I noticed some tenderness and swelling on my fifth metacarpal. It occurred mostly when I went to make a fist or tried to extend my pinkie alone. For a while, I experienced a grinding or grating sensation, but that has since subsided.

That day (Ginger Cracks to Blade Runner) was chill with no tweaky moves, but I did lead every pitch. My hypothesis is that pulling up 1200' of rope in total while belaying from the top is what caused the pain. I've had medial epicondylitis before, so I was belaying off a Munter with the master point at a comfortable height.

It was sore for the rest of the trip (including top-belaying every pitch on Frogland and Epi) but didn't hurt while using any type of hold or jam, so I figured it could be a problem for Future Fritz. Total volume of climbing on the trip was not a problem, nor was intensity.

Per my layman research of peer-reviewed anecdotal evidence submitted by armchair physical therapists, this sounds like inflammation of the tendon sheath (tenosynovitis). I hadn't belayed from the top in several months, so that's my best guess for what caused it.

Mostly professional curiosity at this point, because it doesn't inhibit my climbing or hangboarding, and I'm about to take two weeks off from climbing before hitting the road.

What do y'all think? Anyone else experience something similar?

(Pt Hx: I had a boxer's fracture on that same hand from a previous life. It was sixteen years ago, though, and I haven't had any notable impacts to that zone since.)

I'd say you're onto the problem bud. When I was a guide I would experience similar and 90% of guiding is pulling on a rope.