Some people may also experience pruritus, or severe itching, as a symptom of fibromyalgia. 
Itching may occur in fibromyalgia due to certain nerve fibers being activated and causing an itching sensation. Itching and pain share a common pathway positioned in the spinal cord. ... Initially, scratching relieves the itch, but with constant scratching the skin becomes damaged. 
Just as there is no one cause for fibromyalgia, there isn’t a cause for the unexplained itching. Itching is one possible way your nerves can react to the condition.

It’s also possible that itching could be a side effect of medication you are taking for fibromyalgia, such as pregabalin (Lyrica), duloxetine (Cymbalta), or milnacipran (Savella). Always let your doctor know about any side effects that you experience, even if they are not listed as known side effects. Your doctor may need to adjust your dosage or change your medication.

Itching is a low level pain--so think of it as pain from the fibro. I get it too and nothing you take for itching works--but good control over the fibro does.

I was diagnosed with fibromyalgia before it was a household word. Thirty years ago, in fact, along with atypical connective tissue disease (autoimmune disorders). I have learned over the years that all the symptoms in the world can be attributed to fibro, but also many, many other issues. It is virtually impossible to tease out what is really part of the fibro "syndrome" of symptoms and what isn't. I know people with severe "idiopathic" itching (no diagnosable cause) who do not have fibro or any other symptoms.

I believe we fibro people should
resist the urge to attribute everything under the sun to it. Some are, some may be, some may not be, some aren't. Until there are cold, hard facts, be cautious about calling every hangnail and headache fibromyalgia. I think it's part of the reason we (and fibro) don't get the respect we (it) deserves. It isn't fair, it isn't fun, but it is the reality at this point in time, sadly... Love to all and maybe 2020 will be a year of breakthroughs.

I have had this itching, too. I will get an extremely itchy area but nothing is there! I think it must be the nerves freaking out. It comes and goes at random

I use Claritin take the itching away.