Inflammatory Dermatoses Flashcards

A biopsy of a psoriatic plaque classically shows regular acanthosis, parakeratosis, and collections of neutrophils within the stratum corneum called what?

Answer: Munro microabscesses

Munro microabscesses are neutrophil collections in the parakeratotic stratum corneum characteristic of psoriasis.

Which cytokine pathway is the primary target of biologics like ustekinumab used in moderate-to-severe plaque psoriasis?

Answer: IL-12/IL-23 (p40 subunit)

Ustekinumab blocks the shared p40 subunit of IL-12 and IL-23, central to psoriatic inflammation.

The Auspitz sign, elicited by removing psoriatic scale, represents what pathologic feature?

Answer: Pinpoint bleeding from dilated dermal papillae capillaries

Scraping psoriatic scale exposes thinned suprapapillary epidermis over dilated capillaries, producing pinpoint bleeding.

A patient develops acute generalized pustular psoriasis (von Zumbusch) after abrupt withdrawal of which medication?

Answer: Systemic corticosteroids

Rapid tapering or withdrawal of systemic corticosteroids can precipitate generalized pustular psoriasis.

Guttate psoriasis in a child or young adult is most classically triggered by which preceding infection?

Answer: Streptococcal pharyngitis

Guttate psoriasis frequently follows a group A streptococcal throat infection.

Nail pitting, oil-drop discoloration, and onycholysis in a psoriasis patient raise concern for which associated condition?

Answer: Psoriatic arthritis

Nail involvement in psoriasis correlates strongly with concurrent or future psoriatic arthritis.

The Koebner phenomenon in psoriasis refers to what?

Answer: New lesions appearing at sites of skin trauma

Koebnerization is the development of psoriatic lesions at sites of injury such as scratches or surgical scars.