Okay, so the user provided a question about cicatrising alopecia with perifollicular blue–gray patches and the correct answer is missing. Let me start by recalling what cicatricial alopecias are. They are scarring hair loss conditions where the hair follicles are destroyed. The key here is the perifollicular blue-gray patches, which makes me think of a specific type.

Hmm, cicatricial alopecias can be primary or secondary. Primary ones directly destroy the follicles, while secondary are from other conditions. The blue-gray patches sound like a clinical sign. I remember that lupus erythematosus, specifically discoid lupus, can cause scarring alopecia. The perifollicular pigmentation might be due to post-inflammatory hyperpigmentation or the disease process itself.

Wait, another possibility is lichen planopilaris. That's a primary scarring alopecia too. It presents with perifollicular erythematous-violaceous papules and can lead to scarring. The blue-gray color could be from the inflammatory changes in the skin. Let me cross-check. Discoid lupus has a more classic annular erythematous plaque with central scarring, whereas lichen planopilaris has the perifollicular scaling and pigmentation. Oh, and the perifollicular blue-gray patches are a hallmark of lichen planopilaris. So the correct answer is lichen planopilaris.

Now, the options: A, B, C, D are missing. But the user wants me to explain why the correct answer is right and the others wrong. Let me think of common differential diagnoses. Option A could be discoid lupus, which is a common mistake. But discoid lupus usually has a more distinct annular pattern with central scarring. Option B might be frontal fibrosing alopecia, which is another scarring alopecia but typically affects postmenopausal women and causes recession of the frontal hairline without the blue-gray patches. Option C could be tinea capitis, but that's a fungal infection and would present with scaling, not blue-gray pigmentation. Option D might be alopecia areata, which is non-scarring. So the correct answer is lichen planopilaris. The clinical pearl here is recognizing the perifollicular pigmentation as a key sign. The student should remember that lichen planopilaris is associated with those blue-gray patches and perifollicular scaling, and differentiate it from discoid lupus.

**Core Concept**
Cicatricial (scarring) alopecias result from destruction of hair follicles by inflammatory or neoplastic processes. Perifollicular pigmentation, particularly blue-gray patches, is a hallmark of **lichen planopilaris**, a primary scarring alopecia linked to chronic inflammation and fibrosis.

**Why the Correct Answer is Right**
Lichen planopilaris presents with perifollicular violaceous (bluish-gray) papules, scarring, and progressive hair loss. The blue-gray coloration arises from **interface dermatitis** and **melanin incontinence** (leakage of pigment into the dermis). Histologically, it shows a dense lymphocytic infiltrate at the dermo-epidermal junction, targeting

✓ Correct Answer: B. Whitish lesions in the buccal mucosa