RAS (Recurrent Aphthous Stomatitis) is commonly found painful ulcer on the oral mucosa. It occurs frequently in healthy individuals and has atypical clinical appearance in immunocompromised individuals. The etiology of RAS is still unidentified, but several local, general, immunologic, hereditary, allergic, nutritional, and microbial factors have role to play in causing them. Clinical management of RAS is based on severity of symptoms, frequency, size and number of lesions using topical and systemic therapies. The goals of therapy are to decrease pain and ulcer size, promote healing and decrease frequency of recurrence.

RAS has burning feeling that lasts from 2 to 48 hours before an ulcer appears. It occurs in otherwise healthy individuals and is normally located on the buccal and labial mucosa and tongue. Appearence on heavily keratinized mucosa of the like gums is less frequent.

Diseases which also grounds oral ulcers that may be mistaken for RAS include Behçet’s illness, cyclic neutropenia, recurring intraoral herpes infections, HIV-related oral ulcers or gastrointestinal illnesses such as Crohn’s illness and ulcerative colitis.