Auspitz sign is seen in ?
**Core Concept**
The Auspitz sign is a clinical sign observed during the examination of skin lesions, particularly in cases of psoriasis. It is characterized by the appearance of pinpoint bleeding after scales are scraped off from the surface of the lesions. This phenomenon is due to the thinning of the epidermis and the presence of dilated capillaries.
**Why the Correct Answer is Right**
The Auspitz sign is a result of the abnormal proliferation of keratinocytes in psoriasis, leading to the formation of thick, scaly plaques. When the scales are scraped off, the underlying dilated capillaries are exposed, causing pinpoint bleeding. This sign is most commonly observed in cases of plaque psoriasis, where the epidermis is significantly thickened.
**Why Each Wrong Option is Incorrect**
**Option A:** The Auspitz sign is not typically associated with seborrheic dermatitis, which presents with a different clinical appearance and histopathological features.
**Option B:** While the Auspitz sign can be observed in other skin conditions, it is most characteristic of psoriasis and is not a diagnostic feature of eczema.
**Option C:** The Auspitz sign is not a feature of basal cell carcinoma, which typically presents as a firm, painless nodule or ulcer.
**Clinical Pearl / High-Yield Fact**
The Auspitz sign is a valuable diagnostic clue for psoriasis, particularly in cases where the clinical presentation is atypical.
**Correct Answer:** C. Psoriasis.