Eight days after my third moderna vaccine, I developed generalized hives. The itching began on my scalp and progressed to many other parts of my body. Took a six day cycle of prednisone, hives went away but have been dealing with dermatographia since then. I am on week 6 and taking Blexten (antihistamine) daily. I have tried to stop taking the medication but the itching quickly returns. I also get the occasional spasm in my chest which also seems to be associated with this type of reaction. I am getting progressively concerned as these symptoms persist.