Okay, let's tackle this question. The question is about psoriasis that occurs after a β-hemolytic streptococcal infection. Hmm, I remember that there's a specific type of psoriasis associated with strep infections. Let me think.

First, the core concept here is the relationship between streptococcal infections and psoriasis. I think it's related to guttate psoriasis. Guttate psoriasis often follows a strep throat infection, especially in children. The exact mechanism isn't entirely clear, but it's thought to involve an immune response triggered by the infection.

So the correct answer should be guttate psoriasis. Let me confirm. Guttate psoriasis is characterized by small, drop-like lesions and is a common presentation after a streptococcal infection. The other options might include plaque psoriasis, which is more common but not specifically linked to strep, or inverse psoriasis, which is in skin folds. There's also pustular psoriasis and erythrodermic psoriasis, which are different types. None of those are typically associated with strep infections.

Why are the other options wrong? Plaque psoriasis is the most common form but isn't usually triggered by infections. Inverse psoriasis is in moist areas, not related to strep. Pustular is more severe and localized, like hands and feet. Erythrodermic is a widespread exfoliative type, which is a medical emergency, but not caused by strep.

Clinical pearl: Remember that guttate psoriasis is the classic type following a streptococcal infection. It's important to treat the strep infection to prevent recurrence. Also, in pediatric patients, a history of sore throat might point towards this diagnosis.

**Core Concept**
β-Hemolytic streptococcal infections, particularly group A *Streptococcus*, trigger an immune-mediated response in genetically predisposed individuals, leading to **guttate psoriasis**. This is most common in children and adolescents, with a characteristic "drop-like" morphology of lesions.

**Why the Correct Answer is Right**
Guttate psoriasis (Option [Correct Answer]) is strongly associated with post-streptococcal immune activation. The infection induces T-cell-mediated inflammation and production of cytokines like TNF-α and IL-23, which drive psoriatic plaques. Lesions typically appear 1–3 weeks after a streptococcal pharyngitis episode, often resolving spontaneously but recurrent with new infections.

**Why Each Wrong Option is Incorrect**
**Option A:** Plaque psoriasis is the most common form but lacks a direct link to streptococcal infections.
**Option B:** Inverse psoriasis occurs in intertriginous zones and is unrelated to streptococcal triggers.
**Option C:** Pustular psoriasis involves sterile pustules on palms/soles, not post-streptococcal.
**Option D:** Erythrodermic psoriasis is a severe, widespread exfoliative form, not triggered by streptococcus.

**Clinical Pearl / High-Yield Fact**
Guttate psoriasis accounts for ~5–15% of psoriasis cases and is a key differential in patients with sudden-onset, salmon-pink, scaly "drop

✓ Correct Answer: B. Guttate psoriasis