Cutaneous<unk>  is a self-limiting condition. It usually resolves within 6 to 12 months. Oral<unk>  is a non infectious, chronic inflammatory condition that involves the oral mucosa and may be accompanied by skin lesions. The etiology of oral<unk>  are unknown. It is not clear whether the mechanisms causing isolated oral<unk>  are different from those causing oral<unk>  with cutaneous<unk> . An immune-mediated mechanism where basal keratinocytes are being targeted as foreign antigens by activated T cells, especially CD8+ T cells, has been proposed. Upregulation of intercellular adhesion molecule-1 (ICAM-1) and cytokines associated with T-helper 1 immune response, may also play an important role in the pathogenesis of<unk> . Stress is thought to play a role in the pathogenesis of oral<unk> . Patients with anxiety and depression are reported more commonly with oral<unk>  if compared to normal healthy individuals. Some studies have indicated that stressful events can induce<unk>  lesions in otherwise healthy individuals. However, a cause effect relationship between stress and the onset of oral<unk>  has not been demonstrated. Autoimmune response to epithelial self-antigens remains a possibility. A single study of cutaneous<unk>  reported evidence in support of autoimmunity by expanding in vitro T cells isolated from the skin lesions of two patients, followed by testing the ability of these T cells to kill autologous keratinocytes (cytotoxicity). Several potential triggers of oral<unk>  have been proposed over the years, mainly #Hypersensitivity reaction #* Restorative material (e.g. amalgam and composite) or drugs can cause hypersensitivity reaction and lead to oral<unk> . #* Oral<unk>  usually resolve upon removal of the trigger, as is characteristics of oral<unk>  #Viral infection
Lichen planus
Geographic tongue
Lichen nitidus
Leukoplakia
Lichen simplex chronicus
Lichen myxedematosus
Lichen sclerosus
Tinea barbae