Psoriasis: Pemphigus Vulgaris
Pemphigus Vulgaris:- This is characterized by the development of multiple bullae on the skin and mucous membranes. It is an autoimmune disease. Antibodies are produced by the body against the intercellular material of the prickle cells of the epidermis resulting in lysis of intercellular bridges. This causes rounding of the prickle cells and formation of intraepidermal blisters. The disease is commonly seen in middle aged persons.
The bullae are flaccid, and r rupture easily leaving large erosions. There is no tendency to heal spontaneously. If lateral pressure is applied with finger tip, the superficial layers of skin will slide over the deeper layers. This is called Nikolsky sign Gentle pressure on the top of a bulla causes, peripheral extension of the bulla due to passage of fluid, in between the loosely adherent prickle cells of epidermis. This is called `bulla spread’ sign.
The bullae in the mouth andgenitalia get ruptured easily leaving multiple painful erosions. Conjunctiva of the eyes also may be affected. Diagnosis depends on demonstration of acantholytic cells in smears prepared by scraping the materials from the base of erosions after rupturing an early vesicle or bulla. These cells are epidermal cells which have lost their spines. They are round large cells with a hyperchromatic large round nucleus.
Perinuclear condensation of cytoplasmic material and a halo around it also may be seen. The procedure for demonstration of these acantholytic cells is usually called Tzanck test. Histology also may show many acantholytic cells in the infra epidermal blister.
Tags: Bulla spread, Intraepidermal blisters, Psoriasis, Skin Infection, Tzanck test
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