Jellyfish,

My dad has Dermatomyositis...It's basically the exact same thing as Polymyositis but with a rash...He has a purplish/maroon rash on his face, knuckles and eyelids...He has a lot of pain in his muscles and difficulty with swallowing....He has difficulty getting up from a seated position and extending his arms out and his wrists are affected too...He's also had interstitial lung problems from the disease....Have you ever had any unexplained lung trouble?

Where is the atrophy? MuSK MG can cause facial atrophy...AChR MG usually doesn't result in any atrophy, but could if there's denervation....Polymyositis can cause atrophy too due to destruction of the actual muscle...

You mentioned that you had a droopy eyelid in another post...This isn't a typical feature of ALS or polymyositis, but is often one of the earliest/first symptoms of MG...

Nicky