Aphthous stomatitis is not considered to be true aphthous stomatitis by some sources. Some of these conditions may cause ulceration on other mucosal surfaces in addition to the mouth such as the conjunctiva or the genital mucous membranes. Resolution of the systemic condition often leads to decreased frequency and severity of the oral ulceration. Behçet's disease is a triad of mouth ulcers, genital ulcers and anterior uveitis. The main feature of Behçet's disease is aphthous-like ulceration, but this is usually more severe than seen in aphthous stomatitis without a systemic cause, and typically resembles major or herpetiforme ulceration or both. Aphthous-like ulceration
Aphthous stomatitis vitamin supplements only infrequently improve the ulceration. The relationship to vitamin B12 deficiency has been the subject of many studies. Although these studies found that 0–42% of those with recurrent ulcers suffer from vitamin B12 deficiency, an association with deficiency is rare. Even in the absence of deficiency, vitamin B12 supplementation may be helpful due to unclear mechanisms. Hematinic deficiencies can cause anemia, which is also associated with aphthous-like ulceration. Gastrointestinal disorders are sometimes associated with aphthous-like stomatitis, e.g. most commonly Celiac disease, but also inflammatory bowel disease such as Crohn's disease or ulcerative colitis. The link between gastrointestinal disorders