I get it too, they appear filled with air or some type of plasma or something. Tiny bumps, they usually go away a week or so, and I can pop ‘em.
Yeah, this. I've learned to just scratch them open so the clear plasma escapes, because it resolves the itchiness and I feel like it takes forever to disappear otherwise. Sorta like a blood-blister except exceptionally itchy.
It could be related to a condition I used to have on the bottoms of my feet where itchy blisters would grow, along with dry dead skin. Some sort of fungus, I assume. How should I know? What am I, made of money? Frequent washing kept it in check and eventually cleared it up.
I don't know if the flare ups on my finger joints are related, they seem more like an auto-immune response to pollen. Maybe. Who could ever say
^ All the above is just what I heard from a friend of mine, not me. My body is great and I definitely don't resent it.
Edit: (They do show up in clusters of 1-3 on my fingers, near the joints, and the foot-fungus was over a decade ago so probably unrelated. They seem to be triggered by stress, general immune-response, or possibly by putting contact-stress on the area by, say, holding 2-liter bottles by the neck. Again, there is no accessible science on this matter)
Edit2: This probably goes without saying but one should wash the popped blisters, they're an obvious vector for all sorts of infection.