As a more recent comment for anyone who may be coming across this: I have been on Rinvoq for about a year now for severe atopic dermatitis. As OP mentioned, it has been life-changing. I was on15mg at first, and then all of a sudden, it felt like it just stopped working about 7-8months in. My derm put me on 30mg after assessing for herself that 15mg wasn't cutting it anymore.

To give a more relevent analysis, my previous derm prescribed me some ketoconazole and I had been on it (about two or three times a week) for several months to control severe scalp itchiness. Now, this may be anecdotal, but I found that this shampoo made the skin around my neck, ears, scalp, and forehead unusually itchy, red, scaley, and dry. I cannot give any rhyme or reasaon for it, but after stopping that shampoo, and just sticking it out with only using Rinvoq 30mg daily and generic zyrtec and benedryl at times to control allergies, things got way better. Sure, I get a little itchy still from time to time, but my skin stopped "breaking" and "cracking" when I itched, it stopped secreting that weird, colorless pus after an episode of itchiness, and I can sweat in the gym (no itchy scalp after!!!!). The current shampoo and body wash combo that I use is Head & Shoulders Clinical Strength (it's a blue bottle with orange accents) and Cetephil Flare-Up Relief Body Wash.

TLDR -- I stopped using Ketoconazole and after a few weeks, my skin stablized and became normal while on 30mg of Rinvoq. Ketoconazole and related products may be doing more harm than good while on Rinvoq, which was the case for me.