My brother-in-law has ocular myasenia gravis, and had had it for at least 5 years now. He has now developed a severe rash all over his body, sometimes it looks jus t like a rash, other times it is very lumpy & he does have swelling in his hands & arms. Can myasenia gravis cause this type of rash. He has been to a dermatologist 3 times already & they keep telling him it is hives, he has had this almost 2 months now & has been given antihistamines, which help for a shirt while but then the rash returns.