Which condition is characterized by a positive Auspitz sign?

The condition characterized by a positive Auspitz sign is psoriasis. This sign refers to the appearance of pinpoint bleeding when psoriatic plaques are scraped or removed. It occurs because the scale sits on top of an inflamed layer of skin that contains dilated capillaries; when the scales are removed, these capillaries can be disrupted, leading to bleeding. This symptom is a classic finding in psoriasis and helps differentiate it from other skin conditions.

In the context of the other options, while contact dermatitis, seborrheic dermatitis, and systemic lupus erythematosus can present with various skin manifestations, they do not typically produce the Auspitz sign. Contact dermatitis often shows vesicular lesions and erythema but lacks the characteristic plaques of psoriasis. Seborrheic dermatitis typically displays greasy scales and is not associated with bleeding when removed. Systemic lupus erythematosus may involve a butterfly-shaped rash but does not feature the same type of scaling or the Auspitz sign. Therefore, psoriasis stands out as the condition that reliably shows this specific sign.