DG is a painful localized or generalized gingival lesion characterized by epithelial desquamation, erythema, edema and vesiculobullous lesions. It may often be accompanied by similar lesions involving other oral mucosal tissues but on numerous occasions it represents the only clinical manifestation of an oral disease or disorder. Although DG can be caused by a number of rare or uncommon mucocutaneous diseases, it most often represents clinical features of one of four specific disorders: oral lichen planus, mucous membrane pemphigoid, pemphigus vulgaris or oral contact allergic reactions. At present, many patients are not diagnosed until lesions have become severe although onset of DG is usually gradual and mild manifestations precede more severe lesions. Every effort should be made to accelerate the diagnostic process since dental health care providers have a major responsibility for early detection, diagnosis and treatment or appropriate referral after identifying suspicious lesions.