Erythema Nodosum is also a sign of celiac disease. Celiac can also cause neuropathy, so you need to get worked up for celiac as well as some of these other disorders. Make sure you get a gastroenterologist that knows something about celiac. You will need a few blood tests (one for the gluten antibody) and a stomach biopsy to be certain. Based on the fact that you mention IBS, celiac is a good possibility. If I were you I would get tested for gluten antibodies--they can cause small fiber neuropathy.