title: Chronic oral ulceration.
mesh_terms: D002908:Chronic Disease; D003937:Diagnosis, Differential; D006561:Herpes Simplex; D006562:Herpes Zoster; D006566:Herpesviridae Infections / Q000145:classification*; D006801:Humans; D008010:Lichen Planus; D009059:Mouth Diseases / Q000145:classification*; D010392:Pemphigus