76 страниц. 2015 год. LAP Lambert Academic Publishing Recurrent Aphthous Stomatitis RAS)is a very common disease which carries no mortality but a high morbidity. Incidence of RAS varies from 5% to 50% depending on the ethnic and socioeconomic groups. The most commonly affected population is 10-40 years, who belong to either mid or high socioeconomic class with equal distribution in males and females. RAS is a multifactorial disease and there are several precipitating factors of which stress is the most important. Other associated factors are lack of sleep, minor trauma to oral mucosa in susceptible individuals, menstruation, constipation and food allergies. Although the effect of vitamin B12 and folic acid deficiency was not significant; the combined effect of vitamin B12 deficiency with stress and that of iron deficiency with trauma precipitated the RAS. It is always important to rule out malabsorption syndromes and other systemic diseases in case of haematinic deficiencies.