Traumatic ulcer: This is often the most common cause of oral ulcers, including those on the midline of the tongue, resulting from accidental bites, sharp teeth, or other mechanical injuries.

Aphthous ulcers: Although these are more commonly found on the buccal mucosa, lips, and floor of the mouth, they can occasionally occur on the tongue, including the midline.
Infectious causes (e.g., herpes simplex virus, bacterial infections): These can cause ulcers on various parts of the oral cavity, including the tongue.
Nutritional deficiencies (e.g., vitamin B12, iron, or folate deficiency): These deficiencies can lead to oral changes, including ulcers.

Squamous cell carcinoma: Although less common, any non-healing ulcer in the oral cavity, including the tongue, must be considered for biopsy to rule out malignancy.
Tuberculosis: Oral tuberculosis can present with ulcers, and although rare, it is a critical diagnosis not to miss due to its implications for treatment and public health.
Syphilis: This can cause a variety of oral lesions, including ulcers, and is important to diagnose due to its systemic implications and the need for antibiotic treatment.

Eosinophilic ulcers: These are rare and can be associated with conditions like eosinophilic granuloma or other systemic diseases.
Midline destructive granuloma: A rare condition that can cause destructive lesions of the oral and nasal cavities.
Autoimmune disorders (e.g., pemphigus, pemphigoid): These can cause oral ulcers but are less common and typically involve other areas of the mouth and sometimes the skin.