It includes diseases mainly involving oral mucosa, dermatogic diseases involves oral mucosa, some diseases with both ectoderm and mesoderm origins and oral manifestation of systemic diseases.

• 同时发生于皮肤或单独发生于口腔粘膜上的皮肤疾病；合并起源于外胚层和中胚层的某些疾病的口腔表现；全身或系统性疾病的口腔表现。