Melasma is an acquired hypermelanosis presenting as symmetric hyperpigmented macules and patches on sun-exposed facial skin (centrofacial, malar, mandibular patterns). It results from UV/visible light exposure interacting with genetic, hormonal, and vascular factors, with increased melanogenesis and dermal changes. Management…
Vitiligo is an acquired depigmenting disorder characterized by destruction or functional loss of melanocytes, resulting in well-demarcated depigmented macules and patches. Autoimmunity, oxidative stress, genetic susceptibility, and neurogenic factors contribute to pathogenesis. Disease activity varies from stable to rapidly progressive.…
Dermatitis herpetiformis is a chronic, intensely pruritic, blistering disorder associated with gluten-sensitive enteropathy (celiac disease). It presents with grouped vesicles and excoriated papules on extensor surfaces, buttocks, and scalp. Immunopathology shows granular IgA deposition in dermal papillae. Dapsone provides rapid…
Mucous membrane pemphigoid (MMP), also called cicatricial pemphigoid, is a chronic autoimmune subepidermal blistering disorder primarily affecting mucous membranes with a tendency toward scarring. Common sites include oral, ocular, nasal, pharyngeal/laryngeal, esophageal, and anogenital mucosa; skin involvement occurs in a…
Bullous pemphigoid is the most common autoimmune subepidermal blistering disorder of older adults, characterized by tense bullae on erythematous or urticarial bases and severe pruritus. Autoantibodies target hemidesmosomal antigens BP180 (type XVII collagen, NC16A domain) and BP230 at the dermal–epidermal…
Pemphigus vulgaris is a life-threatening autoimmune blistering disease characterized by flaccid intraepidermal bullae and erosions of skin and mucous membranes due to IgG autoantibodies against desmoglein (Dsg) 3 and, variably, Dsg1. Loss of keratinocyte cohesion (acantholysis) produces fragile blisters, painful…
Periorificial dermatitis (POD) is an inflammatory facial eruption characterized by grouped erythematous papules/pustules and background erythema around the mouth, nose, and/or eyes, often sparing the immediate vermilion border. It is frequently triggered or perpetuated by topical corticosteroids, fluorinated toothpaste, cosmetic…
Rosacea is a chronic inflammatory facial dermatosis with four main phenotypes: erythematotelangiectatic (ETR), papulopustular (PPR), phymatous (including rhinophyma), and ocular rosacea. Pathophysiology includes dysregulated innate immunity, Demodex proliferation, neurovascular hyperreactivity, and barrier dysfunction. Management is phenotype-based: vascular lasers and topical…
Acne vulgaris is a common chronic disorder of the pilosebaceous unit characterized by comedones, inflammatory papules/pustules, and nodules that can lead to scarring and dyspigmentation. Pathogenesis involves follicular hyperkeratinization, excess sebum production (androgen-mediated), Cutibacterium acnes dysbiosis and inflammation, and neuroendocrine/immune…
Pyoderma gangrenosum is a rare, neutrophilic dermatosis presenting as rapidly progressive, painful ulcers with undermined violaceous borders. Pathergy is characteristic. PG is frequently associated with systemic diseases (IBD, arthritis, hematologic disorders). Diagnosis is clinical and by exclusion; biopsy supports a…
