This 42 year-old woman has been diagnosed elsewhere as having "desquamative gingivitis". It is important to remember that this term represents a sign that can be applied to many intraoral lesions which have in common the fact that the superficial layers of the oral mucosal epithelium are lost. The definitive diagnosis of any of those lesions is only achieved by biopsy and immunofluorescent studies. Note the ulcer on the maxillary gingiva at the level of tooth # 8 as well as generalized pronounced gingival erythema.