The 43-year-old singer said she found out about the disease, which is a form of arthritis last year, following extreme pain and other symptoms, reported Ace Showbiz.
"The first symptoms came in the form of food sensitivities. I found I could not touch sugar, starch, caffeine, certain oils, etc, without having a severe reaction that felt like jolts of electricity running through my body," Gibson wrote in a post.
"I felt like a live wire. Talk about 'Electric Youth'!" she revealed, making a reference to her album which was released in 1989.
At the end of the post, the singer left a message to fans who made cruel remarks about her appearance.
"Never judge... Anyone! You never know what someone is going through. I am still in this process and undergoing treatment. But, beyond just 'glimmers of hope,' I actually feel like me again," she posted.