In The Management of Bullous Pemphigoid Dr Tulip Tan Senior Consultant National Skin Centre Bullous pemphigoid is an autoimmune skin disease presenting as a chronic bullous eruption usually in people 60 years and above. Erythematous, eczematised or urticarial - type lesions, annular serpiginous lesions, not unlike the lesions in erythema multiforme may occur 1 to 3 weeks before classical bullae or erosions develop. Pemphigoid nodularis is another uncommon variant presenting as scattered hyperkeratotic nodules and plaques on which bullae may arise. Clinically and histologically similar to prurigo nodularis. A fresh blister is best chosen for skin biopsy including perilesional skin for direct immunofluorescence test.
Histology shows subepidermal blister with an intact epidermis.
Biopsies taken from urticarial lesions before the development of vesicles may show only dermal inflammatory infiltrate of eosinophils and neutrophils with lymphocytes and histiocytes. If an old blister is taken, epithelization may have occurred along the base of the bulla and be mistaken histologically as an intraepidermal bulla. The Salt-split skin procedure separates the normal skin BMZ at the lamina lucida between the cell membrane of the basal cell and the lamina densa so that the lamina densa and all of the other BMZ components beneath it remain on the dermal side of the separation. The severity of disease, age of the patient and presence of underlying diseases especially diabetes mellitus, tuberculosis and hypertension must be considered in determining the dose of corticosteroid. The dose is increased by 10 mg every 5 days if new bulla appear daily.