While many autoimmune diseases are known to be associated with one another (take celiac disease and type I diabetes, for example), few reports exist in the literature documenting what is termed “Multiple Autoimmune Syndrome,” whereby an individual patient manifests three or more autoimmune diseases at the same time. In fact, it is commonly asserted, though not conclusively shown (in my humble opinion), that multiple autoimmune syndrome is rare.
I do not believe that this is accurate. In my limited experience, it seems to me that multiple autoimmunity is actually quite common, particularly in individuals with documented food sensitivities, such as celiac disease/gluten intolerance. When gluten, and other food, sensitivities exist, the gut becomes leaky and allows foodstuffs, bacteria, and other pathogens to pass the intestinal barrier, where they can be detected by the immune system. While everyone likely harbors “self-reactive” immune cells, not everyone mounts an autoreactive immune response, like people with autoimmune disease do. Pathogen (food, bacteria, or otherwise) encounter by the immune system in the gut delivers inflammatory signals, that may then lead to the activation and response of autoreactive immune cells. In fact, current data suggests that all autoimmune diseases may begin in the gut.
Because of the supposed rarity of multiple autoimmune syndrome, my favorite articles are case studies of individuals with multiple autoimmunity. In the case reported here, a 24-year-old female presents with lichen planus (a suspected autoimmune disease), lupus (a known autoimmune disease), and hashimoto’s thyroiditis (also called autoimmune hypothyroidism), and to date, it is the first association of it’s kind.