**1. Introduction**

Oral ulcerative lesions are defects in the oral epithelia, its underlying connective tissue or both. The oral mucosa is considered among one of the susceptible areas in the human body to painful ulceration [1, 2]. An oral ulcer is not a disease itself but rather a sign of a different underlying condition, therefore it is usually challenging to diagnose the accurate etiology [1]. It is important to identify the etiologic factor to provide a complete resolution to patients rather than constantly prescribing certain medicines to suppress the symptoms [3].

Regardless of the etiology of these lesions, oral ulcerative lesions may be categorized as minor, major or herpetiform ulcerations. Minor ulcerations are usually less than 1 cm in diameter, and they most commonly present on the labial or buccal mucosa or the ventral surface of the tongue. Less common locations include the dorsum of the tongue, hard palate or the gingiva [4, 5].

Ulcerations that measure more than 1 cm in diameter are referred to as major oral ulcerations and have a lower prevalence than minor ones. Among these three types, the least common type is the herpetiform ulceration, which unlike what its name suggests, is irrelevant to herpetic stomatitis since no vesicle formation is observed in advance [5]. These type of ulcerations are multiple and usually are much smaller in diameter (1–3 mm) [4].

Another helpful classification is based on the duration of these lesions, which may aid clinicians establish a more logical stepwise progression towards an accurate diagnosis. Accordingly, an oral ulcerative lesion is diagnosed as acute if it lasts for less than two weeks, chronic if it persists for more than two weeks or recurrent if it presents with a history ulcerative episode with intermittent periods of healing [1].
