I developed cryoglobulinemia, an immune vasculitis, triggered by Covid 12/22. I was treated with Plasmapheresis (which resolved the rapid onset alopecia I also developed post-Covid that was not responding to high doses of prednisone or Kenalog scalp injections). I'm now testing negative for cryoglobulins, and having very minimal skin reaction with cold exposure. My medical dermatologist has no idea if this might be a problem for me, but she does not do Microneedling in her practice.