causes mucous membrane pemphigoid. It also occurs after acute severe ocular inflammation in patients with Stevens-Johnson syndrome. Pathophysiology Autoantibodies target the basement membrane zone proteins which are responsible to promote adhesion within the basement membrane zone of the mucosa and the skin. The major basement membrane zone proteins identified include : C-terminus of BP180 BP230 Laminin 332(also known as laminin 5 or epiligrin) Alpha-6-beta-4 integrin Type VII collagen. In contrast to the target of the N-terminus of BP180 that is located in the hemidesmosomes and upper lamina lucida in bullous pemphigoid, the target antigen in MMP is the C-terminus of BP180 which is located in the lower lamina lucida and lamina densa. This results in a deeper separation that is more likely to scar as compared to a more superficial blister that is unlikely to scar in bullous pemphigoid. Antibodies to the beta-4 integrin subunit of alpha-6-beta-4 integrin is shown to be associated with ocular disease while oral involvement is suggested to be linked with antibody reaction towards the alpha-6 subunit. Besides, MMP with antibody reaction against laminin 332 has an association with an increased risk for internal malignancy. Similar to bullous pemphigoid, other factors such as genetic factors, environmental exposures and the phenomenon of epitope spreading potentially result in MMP. Multiple studies have also reported an association of HLA-DQB1*0301 with MPP. Diagnosis Diagnosis of bullous pemphigoid includes clinical assessment, skin biopsy for histopathology and direct immunofluorescence, indirect immunofluorescence and ELISA test. Among all, direct immunofluorescence is the gold standard for diagnosis of mucous membrane pemphigoid. Clinical assessment Presence of tense blisters and erosions that occur on skin without another identifiable cause. Desquamative gingivitis or mucositis involving oral, ocular, nasal, genital, anal, pharyngeal, laryngeal, and/or esophageal mucosae Presence of pruritic eczematous eruptions, or urticarial plaques without identifiable cause. Patient's age over 60 years old. Histopathology Lesional tissue, preferably of an intact vesicle or the edge of an intact bulla is obtained using punch biopsy for Haemotoxylin and Eosin (H&E) staining. The findings are sub-epidermal blister with dermal infiltrated with lymphocytes, neutrophils and eosinophils. Additional findings include sub-epidermal fibrosis which is consistent with the scarring nature of mucous membrane pemphigoid in older lesions and plasma cell infiltration. Direct immunofluorescence studies Direct immunofluorescence (DIF) studies involves directly detecting tissue bound antibodies. Biopsy specimens for DIF should be taken from perilesional skin instead of lesional skin for H&E histopathologic evaluation. Linear band of