Tongue ulcers appear in a myriad of infectious, autoimmune, metabolic, malignant and iatrogenic conditions, and their duration, presence of pain, location, as well as progression is key in determining the underlying cause. History taking, a thorough physical examination, and a broad laboratory workup are vital steps during the diagnostic workup.
Ulcerations in the oral cavity are relatively common in general practice, with estimates suggesting that up to 4% of the population in the United States suffer from some form of ulcerative lesion, and the tongue is one of the sites where they may develop  . The reason for this rather high prevalence rate is the diverse etiology      :
In most cases, tongue ulcers have a benign and self-limiting course with spontaneous resolution within several days or a few weeks , but in the setting of persistent, more severe damage to the tongue and oral mucosa, the cause of ulceration may require specific treatment.
The diagnostic workup of tongue ulcers must be detailed and comprehensive. The physician must obtain a thorough patient history, which will encompass the onset, course, and progression of ulcers    . Furthermore, patients should be asked about their sexual habits (to exclude syphilis and HIV), recent dental or medical procedures in the oral cavity (to exclude trauma), and the use of drugs such as aspirin and cytotoxic agents  . Conversely, a full inspection of the oral cavity, and not only the tongue, will warrant visualization of oral ulcers that might be missed without appropriate illumination and clinical suspicion. The size, shape, location, and the appearance (color, induration, and other associated features) should be assessed  . The initial diagnosis is made based on clinical criteria, but laboratory studies might be employed to assist in determining the underlying pathology, including a complete blood count (CBC), serum inflammatory markers (C-reactive protein and erythrocyte sedimentation rate, or CRP and ESR, respectively), anti-nuclear antibodies (ANA), and a basic biochemical panel. Vitamin deficiencies (primarily B12 and folate, but also iron) are well-established risk factors for ulcers of the tongue and oral cavity , and their levels should be evaluated as well. Biopsy of the tongue ulcer, however, and subsequent histopathological examination is quite useful, and is recommended whenever possible   .