Subepidermal bullae is seen in
Bullous pemphigoid is an autoimmune pruritic skin disease preferentially in elderly people, that may involve the formation of blisters (bullae) in the space between the epidermal and dermal skin layers. The disorder is a type of pemphigoid. It is classified as a type II hypersensitivity reaction, with the formation of anti-hemidesmosome antibodies Pathophysiology: The bullae are formed by an immune reaction, initiated by the formation of IgG autoantibodies targeting Dystonin, also called Bullous Pemphigoid Antigen 1, and/or type XVII collagen, also called Bullous Pemphigoid Antigen 2, which is a component of hemidesmosomes. A different form of dystonin is associated with neuropathy. Following antibody targeting, a cascade of immunomodulators results in a variable surge of immune cells, including neutrophils, lymphocytes and eosinophils coming to the affected area. Unclear events subsequently result in a separation along the dermoepidermal junction and eventually stretch bullae. Diagnosis: Diagnosis consist of at least 2 positive results out of 3 criteria (2-out-of-3 rule): (1) pruritus and/or predominant cutaneous blisters, (2)linear IgG and/or C3c deposits (in an n- serrated pattern) by direct immunofluorescence microscopy (DIF) on a skin biopsy specimen, and (3)positive epidermal side staining by indirect immunofluorescence microscopy on human salt-split skin (IIF SSS) on a serum sample. Routine H&E staining or ELISA tests do not add value to the initial diagnosis. Treatment: Treatments include class I topical steroids (clobetasol, halobetasol, etc.) , systemic prednisone and powerful steroid-free immunosuppressant medications, such as methotrexate, azathioprine or mycophenolate mofetil. Some of these medications have the potential for severe adverse effects such as kidney and liver damage, increased susceptibility to infections, and bone marrow suppression. Antibiotics such as tetracycline or erythromycin may also control the disease, paicularly in patients who cannot use coicosteroids. The anti-CD20 monoclonal antibody rituximab has been found to be effective in treating some otherwise refractory cases of pemphigoid. Ref Harrison 20th edition pg 1278
Pemphigus vulgaris
Darriers disease
Bullous pemphigoid
HSV infection
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