I was diagnosed with Autoimmune disease many years ago. At one time they thought is was RA. I get these blisters. So are very small, others (like on the pad of my thumb) are large. When the skin comes off, it is red and painful and red. It almost always seems t happy on my thumbs. It used to be worse when I was on Methotrexate. The doctor said it is a symptom of the autoimmune disease. If I eat something that i am sensitive to like Tomato, potato, eggplant, peppers, banana avocado, kiwi or gluten...I get swelling in my joints as well. This is because the foods trigger the immune response as if I have eaten something bad. It just doesn't know when to shut off,
I cannot said that anyone has autoimmune disease, I am not a doctor... I am only sharing what is wrong with me.