Check your city water if you have it. Go to EWG.org and type in your zip code. I installed a shower filter because my city water is full of gross things. My water report got an F minus with 34 dissolved solids over the limit. Never use hot water on your skin. But water full of chemicals will cause itching.

I got a New Filtered Showerhead, years ago & change mine every so often, just cuz🙋🏼‍♀️& that HOT WARM IS MURDER on OUR SKIN. I always rinse at the end in a quick COLD RINSE, feels Great, Refreshing. Plus a Humidifer has been my BEST FRIEND, I have mine on Allday, yes refill needed but is heaven to my SKIN, all my SURFACES
Best of luck , i also have a few in other areas where i hang out the most HIMIDIFER that is 🙏

You might want to talk to a dermatologist or rheumatologist whichever one you're seeing more easily about that side effect. Let them know it's intense and uncomfortable. They may be able to prescribe something that helps more than OTC moisturizing, or certain ways to counteract that possibly otherwise? Worth a try. Hope you find relief soon. That time of year when things are changing with the weather and my plaques are itching. Just because they're flaring up I'm guessing now.

I find salicylic acid products help but I don't have it widespread fortunately. But any amount is unpleasant and uncomfortable.

Delayed itchiness after light therapy sessions can definitely happen, even with immediate moisturizing. Phototherapy is a fantastic treatment for psoriasis, but it can sometimes cause a temporary histamine response or intense dryness as the skin cells react. Please know you aren't alone in experiencing this. Make sure to double-check with your dermatologist or phototherapy nurse to see if a specific type of emollient or an over-the-counter anti-itch solution might help soothe your skin after your sessions!🤙🏻