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What is Berkley membrane is seen in the following cutaneous condition: and explain in detail?
Psoriasis is characterized by well-circumscribed, sharply demarcated erythematous papules and/or plaques. These are covered by dry, brittle, silvery or grayish white, loosely adherent, micaceous scales. The scales are disposed in lamellar fashion. Occasionally a white blanching ring is seen around the psoriatic lesions, known as Woronoff ring. On grattage, silvery white scales come off in layers. After their removal, a characteristic coherence is observed, as if one scratches on a wax candle (candle grease sign). On fuher grattage, a thin peel like membrane, Berkley's membrane, is seen which comes off as a whole. On its removal, a wet surface with multiple pinpoint bleeding is revealed. This is called Auspitz sign. Ref: Textbook of Clinical Dermatology By Sehgal, 4th edition, Page 127.