Patient presents with complaint of oral ulcer or mouth sore.  Location of the ulcer is documented as (e.g., labial mucosa, buccal mucosa, tongue, gingiva, soft palate).  Size of the ulcer is approximately (measurement in mm or cm) and is described as (e.g., round, oval, irregular).  The ulcer's appearance is characterized as (e.g., erythematous, white, yellow, fibrinous, pseudomembranous).  Associated symptoms may include pain, burning, tingling, bleeding, difficulty eating or speaking, or dysgeusia.  Differential diagnosis includes aphthous ulcer, traumatic ulcer, recurrent herpes simplex virus infection, hand foot and mouth disease, herpangina, Behcet's disease, pemphigus vulgaris, squamous cell carcinoma, and other oral lesions.  Etiology may be related to trauma, infection, autoimmune disease, nutritional deficiency, or idiopathic factors.  The patient's medical history, medication list, and social history including tobacco and alcohol use were reviewed.  Diagnosis of oral ulcer is made based on clinical presentation.  Treatment plan includes (e.g., topical corticosteroids, pain management with over-the-counter analgesics, antimicrobial mouthwash, instructions for good oral hygiene).  Patient education provided regarding proper oral care, avoidance of irritants, and follow-up care if symptoms do not improve or worsen.  ICD-10 code (e.g., K12.0 for aphthous ulcer, other codes as appropriate) is assigned.  Follow-up scheduled as needed.