Random Itching with Fibromyalgia

I have Fibromyalgia and something called Mast Cell Activation Syndrome (MCAS). From what I've heard, it's very common in people with Fibromyalgia and EDS. I think the itchiness/rashes I experience can usually be attributed to MCAS, but considering how many health issues can be caused by Fibro, I wouldn't be surprised if Fibro can cause an itchy response. Do you notice if there are any triggers that set off the itchiness? (Certain foods, temperature change, stress, etc?) Maybe look into MCAS as well as more info on Fibro and rashes to see if you resonate with any other symptoms and maybe that might help narrow it down to whether it's a Fibro response or something else.