Editor’s note: This is the fourth and final installment in a series of columns about the similarities and the differences among IBD, Crohn’s disease, colitis, IBS and celiac disease. Read parts one here, two here, and three here. Inflammatory bowel diseases like Crohn’s, ulcerative colitis (UC) and other autoimmune diseases of the gastrointestinal tract can be confusing and hard to recognize. These diseases can be so different, and yet alike, that the distinctions among them can be hard to understand. Knowing what these differences are, and which disease you or your friends suffer from, can help you understand the differences. Here, we'll look at IBD and celiac. Celiac disease, also spelled coeliac, is often miscategorized as an inflammatory bowel disease. Celiac is considered to be an autoimmune reaction to gluten. And although celiac is not a part of the IBD umbrella, gluten does cause an immune response to attack within the body, much like Crohn’s and ulcerative colitis. But, like IBD, Celiac is also considered an autoimmune disease. Gluten, found in bread, pasta and similar foods, wheat and barley, causes inflammation and reaction within people who are intolerant. The small bowel is often affected, leaving patients to suffer many symptoms relatable to IBD, such as diarrhea, bloating, pain and vomiting. With celiac disease, a blood test can help with diagnosis, a tissue transglutaminase antibodies test (tTG-IgA), and a biopsy from the small bowel also are used for diagnosis. Celiac patients can maintain healthy lifestyles through gluten-free diets and avoiding gluten cross-contamination as much as possible.