neutropenia, there is a reduction in the level of circulating neutrophils in the blood that occurs about every 21 days. opportunistic infections commonly occur and aphthous-like ulceration is worst during this time. hematinic deficiencies (vitamin b12, folic acid and iron), occurring singly or in combination, and with or without any underlying gastrointestinal disease, may be twice as common in people with ras. however, iron and 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 have a 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 and aphthous stomatitis is probably related to nutritional deficiencies caused by malabsorption. less than 5% of people with ras have celiac disease, which usually presents with severe malnutrition, anemia, abdominal pain, diarrhea and glossitis (inflammation of the tongue). sometimes aphthous-like ulcerations can be the only sign of celiac disease. despite this association, a gluten-free diet does not usually improve the oral ulceration. other examples of systemic conditions associated with aphthous-like ulceration include reactive arthritis, and recurrent erythema multiforme. diagnosis