for histopathology and direct immunofluorescence, indirect immunofluorescence and ELISA test. Among all, direct immunofluorescence is the gold standard for diagnosis of bullous pemphigoid. Clinical assessment For patients greater than 70 years old Blistering skin disease characterized by the presence of tense blisters and erosions that occur without another identifiable cause and rarely on mucosa. Unexplained pruritus, pruritic eczematous eruptions, or urticarial plaques 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. Typical histopathologic findings include: Sub-epidermal split with numerous eosinophils within the cleft. A superficial dermal inflammatory cell infiltrate of variable intensity with lymphocytes, eosinophils, and neutrophils. Eosinophlic spongiosis (Specifically in early lesion or may be seen in clinically erythematous skin surrounding the blister) Direct immunofluorescence 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. DIF specimens should be placed in Michel's solution or Zeuss transport media instead of formalin. DIF of bullous pemphigoid will show the presence of fine, continuous and linear deposits of IgG and/or C3 along the epidermal basement membrane. Other classes of immunoglobulins such as IgM and IgA are present in approximately 20% of cases and usually are less intense. In some cases with the deposits of IgA, patient may have oral lesion. At early stages of the disease, only C3 may be present. Indirect immunofluorescence Indirect immunofluorescence is used to detect circulating antibodies targeting the antigens at the basement membrane zone in patients with pemphigoid. In this procedure, patient's serum is collected and overlaid on salt-split normal human skin and incubated. Following this, the specimen will be stained for fluorescent detection of antibodies. In bullous pemphigoid, circulating IgG targeting the basement membrane, mainly BP180 and BP230 hemidesmosomal proteins are detectable in 60-80% of patients. IgA and IgE classes can also be detected, but less frequently. Enzyme-linked immunosorbent assay (ELISA) ELISA for bullous pemphigoid are commercially available to test for circulating Ig against NC16A domain of BP180 and BP230, known as bullous pemphigoid antigen 2 [BPAg2] and bullous pemphigoid antigen 1 [BPAg1] respectively. Antibodies to BP180NC16A domain is useful for the diagnosis of bullous pemphigoid as it has a sensitivity of 89% and specificity of 98%. Detection of BP180 and/or BP230 antibodies in serum does not give a confirmative diagnosis of