Pityriasis rubra pilaris (PRP) Type I (adult classic) has a distinguishing clinical sign that helps differentiate it from extensive plaque psoriasis. Which feature is characteristic of PRP?

• A Silvery micaceous scale with positive Auspitz sign
• B Involvement restricted to sun-exposed sites
• C Nail pitting and oil drop sign
• D Islands of spared normal skin within erythroderma and follicular keratotic papules (nutmeg grater) ✓

Explanation

PRP is characterised by: follicular keratotic papules with a 'nutmeg grater' feel (perifollicular acanthosis), salmon-orange erythroderma progressing cephalocaudally, and pathognomonic 'islands of spared normal skin' within the erythrodermic areas. The Auspitz sign, silvery scale, nail pitting, and oil drop sign are features of psoriasis. The orange tinge of PRP palmoplantar keratoderma (PPK) also helps differentiation.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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