A 32-year-old man has well-defined erythematous plaques with silvery-white scales over elbows and scalp for 5 years. On removing the scales, a bleeding point is seen. Nail examination shows pitting and onycholysis. Which sign describes the bleeding point on scale removal?

• A Auspitz sign ✓
• B Koebner's phenomenon
• C Grattage sign
• D Candle grease sign

Explanation

Auspitz sign is pathognomonic of psoriasis and refers to the appearance of pinpoint bleeding when the silvery scale is removed from a psoriatic plaque. This occurs because the dermal papillae are elongated and their thinly covered capillaries are exposed when the suprapapillary epidermis is disrupted. The grattage test involves scraping the scale to reveal a shiny membrane (pelucid membrane) beneath, followed by Auspitz sign. Candle grease sign refers to the whitish appearance of scales when scratched, like a candle.

Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.

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