AOBD Dermatology flashcards

33 cards. Read the term and the definition here. The deck at the top of this page is optional.

Auspitz sign

Pinpoint bleeding that occurs when scale is removed from a psoriasis plaque, reflecting thinned suprapapillary epidermis over dilated dermal capillaries.

Nikolsky sign

Separation of the epidermis with gentle lateral pressure, indicating intraepidermal cleavage; positive in pemphigus vulgaris and staphylococcal scalded skin syndrome.

Pemphigus vulgaris DIF

Direct immunofluorescence shows intercellular IgG deposits in a net-like pattern within the epidermis, consistent with desmoglein autoantibodies.

Bullous pemphigoid DIF

Direct immunofluorescence demonstrates linear deposits of IgG and C3 along the basement membrane zone, indicating autoantibodies against hemidesmosomal proteins.

Dermatitis herpetiformis DIF

Granular IgA deposits in dermal papillae are characteristic; associated with gluten-sensitive enteropathy and treated with dapsone or gluten-free diet.

Basal cell carcinoma features

Pearly papule with telangiectasia and rolled border; nodular, superficial, and morpheaform subtypes exist; locally invasive but rarely metastasizes.

Melanoma ABCDE criteria

Asymmetry, Border irregularity, Color variation, Diameter greater than 6 mm, and Evolving lesion guide clinical recognition of melanoma.

Miliaria crystallina

Obstruction of eccrine ducts at the stratum corneum produces clear superficial vesicles without inflammation, often in neonates.

Miliaria rubra

Deeper eccrine duct obstruction in the epidermis causes erythematous papulovesicles, commonly in skin folds and occluded areas.

Erythema toxicum neonatorum

Blotchy erythema with pustules containing eosinophils appearing in the first days of life; self-limited and requires no treatment.

Transient neonatal pustular melanosis

Pustules present at birth that rupture to leave hyperpigmented macules with collarette scale; benign and self-resolving without therapy.

Kawasaki disease criteria

Fever for at least 5 days plus 4 of 5 features: rash, conjunctivitis, oral changes, extremity changes, cervical lymphadenopathy; risk of coronary aneurysms.

Staphylococcal scalded skin syndrome

Exfoliative toxin causes superficial epidermal cleavage with Nikolsky-positive desquamation; treated with antibiotics, typically in children.

Hemangioma of infancy

Vascular tumor appearing shortly after birth that proliferates then involutes; complications include ulceration and airway obstruction.

Tinea capitis in children

Scalp dermatophyte infection, often Trichophyton tonsurans, presenting with scaling, alopecia, or kerion; requires oral antifungal therapy.

Mohs surgery indication

Used for basal cell and squamous cell carcinoma in high-risk sites or with aggressive histology, recurrent tumors, and ill-defined borders.

Mohs margin examination

Frozen sections examine 100 percent of peripheral and deep margins by mapping and en face sectioning of excised tissue.

Mohs stages

Each stage involves excision, mapping, orientation with inks, freezing, sectioning, and microscopic examination, repeated until margins are clear.

Mohs tissue mapping

A grid with marks correlates the clinical defect with histologic sections, allowing precise localization of residual tumor.

Mohs contraindications

Tumors with extensive subclinical spread or those requiring reconstruction beyond Mohs capability are generally not suitable for Mohs surgery.

Mohs for melanoma

May be used with immunohistochemistry such as MART-1 and specialized training to assess margins in melanoma.

Lichen planus histology

Hyperkeratosis, wedge-shaped hypergranulosis, saw-tooth rete ridges, and band-like lymphocytic infiltrate at the dermoepidermal junction.

Psoriasis histology

Regular acanthosis, thinned suprapapillary plates, parakeratosis, and Munro microabscesses of neutrophils in the stratum corneum.

Pemphigus histology

Suprabasal acantholysis with tombstoning of basal cells; direct immunofluorescence shows intercellular IgG deposits.

Dermatitis herpetiformis histology

Subepidermal blisters with neutrophilic microabscesses in dermal papillae; direct immunofluorescence shows granular IgA.

Mycosis fungoides histology

Epidermotropism of atypical lymphocytes with cerebriform nuclei and Pautrier microabscesses within the epidermis.

Seborrheic keratosis histology

Horn cysts, pseudohorn cysts, basaloid cells, and melanin pigment characterize this benign epidermal proliferation.

Actinic keratosis histology

Atypical keratinocytes in the lower epidermis with parakeratosis and solar elastosis in the dermis, reflecting chronic sun damage.

Direct immunofluorescence role

Essential for autoimmune blistering diseases; the location and pattern (intercellular, linear, or granular) guide the specific diagnosis.

Psoriasis Koebner phenomenon

New psoriatic lesions develop at sites of skin trauma, a feature shared with lichen planus and vitiligo.

Scabies diagnosis

Mineral oil scraping of burrows in web spaces shows mites, eggs, or scybala; nocturnal pruritus is characteristic and contacts require treatment.

Kerion

Boggy inflammatory scalp mass due to dermatophyte infection, often with alopecia; requires oral antifungal therapy to prevent scarring.

Munro microabscess

Collection of neutrophils within the stratum corneum, a histologic hallmark of psoriasis seen alongside parakeratosis and acanthosis.