Pattern of Skin Inflammation

Chronic persistent, relapsing, scaling skin condition, red plaques with silvery scales

Psoriasiform Dermatitis

Rapid epidermal cell turnover resulting in marked epidermal thickening of the stratum corneum

Psoriasiform Dermatitis/ Psoriasis

Cornified layer contains cells with retained nuclei, a pattern that reflects the increased epidermal turnover.

Parakeratosis

Too many cells are being made

Psoriasiform Dermitis/Psoriasis

Interface Dermatitis

Dense Infiltrate of Lymphocytes (mostly T lymphocytes) along the Derma-Epidermal Junction.

Hyperkeratosis

Epidermal Thickening of Stratum corneum

Parakeratosis

Retained Nuclei in the cornified layer (outermost layer)

Interface Dermatitis

Characterized by a dense infiltrate of lymphocytes (mostly T lymphocytes) directly along the dermal-epidermal junction (DEJ)

Keratinocytes

Primary cell type of epidermal Layer

Spongiosis

Intracellular edema of skin cells that that pushes keratinocytes apart and creates visible spaces between them.

Allergic Contact Dermatitis

A delayed hypersensitivity immune-mediated reaction caused by skin contact with an allergen.

Mucule

Flat, non-palpable, pigmented lesion < 1 cm.

Patch

Flat, non-palpable, pigmented area ≥ 1 cm.

Two types of flat skin lesion

Mucule and Patch

Papules

Elevated, solid, palpable lesion < 1 cm

Plaques

Elevated, solid, palpable lesion ≥ 1 cm

Two types of solid, elevated skin lesions

Papule and Plaque

Nodules

Solid, rounded, firm lesion extending deep into the dermis; diameter is roughly equal to thickness.

Vesicles

Fluid-filled small blisters < 1 cm

Bullae

Fluid-filled large blisters ≥ 1 cm

Pustule

A vesicle or bulla containing purulent exudate/pus

Vesiculobullous Dermatitis.

Separation of skin layers causing fluid-filled spaces. Can be intraepidermal or subepidermal. May feature acantholysis(loss of intercellular connections between keratinocytes).

acantholysis

Loss of intercellular connections between keratinocytes (can be found in Vesiculobullous Dermatitis)

Vasculitis

Small vessel inflammation driven by immune complexes that recruit neutrophils