Term
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Definition
| Flat lesion differs only by color & less than 5mm |
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Term
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Definition
| Flat lesion that differs from surrounding skin only by color and greater than 5 mm |
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Term
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Definition
| Solid, elevated lesion < 5 mm |
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Term
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Definition
| Elevated, flat-topped lesion > 5 mm |
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Term
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Definition
| Firm, edmatous, flat-topped papule or plaque resulting from infiltration of dermis w/ fluid that lasts < 24hrs |
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Term
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Definition
| Circumscribed, elevated collection of fluid that is < 5mm |
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Term
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Definition
| Circumscribed, elevated collection of fluid taht is > 5mm |
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Term
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Definition
| Elevated collection of purulent fluid that varies in size |
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Term
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Definition
| Solid, palpable lesion located under the epidermis |
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Term
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Definition
| Abnormal shedding or accumulation of stratum corneum |
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Term
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Definition
| Dried serum, blood or purulent exudate on the skin |
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Term
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Definition
| Linear or punctate erosion of epidermis secondary to scratching |
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Term
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Definition
| Focal loss of epidermis which does not penetrate the dermoepidermal jxn and heals w/o scarring |
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Term
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Definition
| Depressed lesion with focal loss of epidermis and dermis that heals w/ scarring |
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Term
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Definition
| Thickened skin w/ accentuation of skin lines secondary to chronic rubbing |
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Term
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Definition
| Increased thickness or hyperplasia of the cornified layer |
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Term
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Definition
| Hyperkeratosis in which pyknotic nuclei are retained in cornified layer |
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Term
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Definition
| Increased number of cells in the granular layer |
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Term
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Definition
| Epidermal hyperplasia (specifically increased number of cels in the spinous layer) |
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Term
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Definition
| Form acanthosis that has dilated projections above the skin surface |
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Term
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Definition
| Edema b/w the spinous cells resulting in widening of the intercellular spaces |
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Term
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Definition
| Premature abnormal keratinization of cells having eosinophilic cytoplasm and small, darkly staining nuclei |
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Term
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Definition
| Loss of cohesion b/w epidermal cells that leads to intraepidermal clefts & vesicles |
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Term
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Definition
- Common inflammatory rxn of skin
- Characterized in clinic by Pruritis
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Term
| Allergic Contact Dermatitis |
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Definition
- Type IV delayed hypersensitivity rxn (previously sensitized individuals reexposed to antigen)
- Acute: Erythematous oozing papules & vesicles
- Poison Ivy - Linear
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Term
| Irritant contact dermatitis |
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Definition
- Nonallergic reaction w/ no prior sensitization
- Agents cause damage to skin
- Occurs in any individual who contacts a significant concentration of agent
- Rash looks painted on
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Term
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Definition
- Very common chronic disease
- Genetic predisposition
- Clinical presentation dependent on age
- Infants: acute/subacute eczema with oozing of crusted papules on head, neck, extensor surfaces
- Older children/adults: Chronic eczema with scaling and lichenification
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Term
| Acute spongiotic dermatitis |
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Definition
- Epidermal spongiosis & papillary dermal edema
- Intraepidermal vesicle formation secondary to spongiosis
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Term
| Chronic eczematous dermatitis |
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Definition
- Hyperkeratosis
- Acanthosis
- Mild spongiosis but no vesicles
- Thickening of dermal collagen & vertical streaking w/ chronic scratching
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Term
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Definition
- Vascular reaction causing pruritic wheals (may be surrounded by a halo)
- Acute < 6 weeks; Chronic > 6 weeks
- Type I IgE mediated hypersensitivity rxn
- Mast cells release histamine -> increase in vacular permability -> leakage of fluid and edema into surrounding tissue
- Angioedema of lips & eyes most common
Histopathology
- Dermal edema: Collagen bundles are seperated by edema
- Perivascular and interstitial infiltrate often with neutrophils and eosinophils |
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Term
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Definition
- Commonly Triggered by infections (HSV)
- 'Target' or 'Iris' Lesion w/ 3 zones
- Central dusky purpura or vesicle
- Elevated, edematous pale ring
- Peripheral rim of macular erythema
- Symmetric distribution on hands & feet
Treatment
- If recurrent and related to HSV - suppressive oral antiviral therapy |
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Term
Stevens-Johnson Syndrome (SJS)
&
Toxic Epidermal Necrolysis (TEN) |
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Definition
- Associated with drug reactions
- Febrile prodome
- **Mucouse membrane involvement prominent**
- Lesions are more diffuse & become confluent
- SJS - 10% of body surface area
- Overlap - 10-30%
- TEN - > 30% body surface involvement
Histopathology (Erythema Multiforme as well)
- Vacuolar interface pattern = damage to basal cells w/ vacuole formation
- Vacuolizations leads to subepidermal blister
- Inflammatory infiltrate at dermal-epidermal junction
- Necrotic keratinocytes initially in basal layer and extend upward (amount of epidermal necrosis increased w/ SJS/TEN)
Treatment
- Hospitalize and treat as burn patient
- Systemic steroids, IVIg for TEN |
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Term
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Definition
- Chronic inflammatory disorder which affects 1-2% of US population
- 27 yo avg. age of onset
- Genetic predisposition
- T lymphocytes & cytokines
Dx
- Auspitz's sign: Pinpoint bleeding when scale is forcibly removed secondary to thinning of epidermis over tips of dermal papillae
- Koebner phenomenon: appearance of lesions at sites of trauma
Histopathology
- Hyperkeratosis
- Neutrophils in stratum corneum = Munro microabscesses
- Regular epidermal acanthosis
- Decreased granular layer
- Epidermal thinning over dermal papillary tips
- Dilated vessels in dermal papillae
Rx
- Topical steroids or retinoids
- Light therapy w/ PUVA, UVB
- Systemic therapy w/ oral retinoids, methotrexate or Biologic agents
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Term
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Definition
- Well demarcated erythematous plaques + white scale
- Scalp, nails, extensor extremities, elbows, knees
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Term
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Definition
- Erythematous scaly papules
- Diffusely distributed
- Abrupt onset usually after acute infection (Streptococcal pharyngitis)
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Term
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Definition
5 P's: Pruritic, planar, purple, polygonal papules
- Flexor surfaces of wrists & forearms
- Onset b/w 30-0 yoa
- Increased incidence in pts. w/ hep. C
- Immunologic rxn of helper T cells
Dx
- Wickham's striae: lacy, reticulated pattern of criss-crossed whitish lines
- 50% have mucous membrane involvement
Histopathology
- Hyperkeratosis
- Focal wedge-shaped hypergranulosis
- 'saw-tooth' pattern of irregular acanthosis
- Lichenfold infiltrate: Dense band-like dermal infiltrate of mainly lymphocytes 'hugging' underside of epidermis
- Basal cell layer damage (vacuolization) -> pigment incontinence
- Civatte bodies: necrotic keratinocytes
Rx
- Topical corticosteroids
- Rarely systemic steroids or other immunosuppressive agents |
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Term
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Definition
- Autoimmune blistering disorder
- Loss of intercellular cohesion
- Ags to Desmoglein-1 & Desmoglein-3
- 5-6th decades
- Flaccid blisters & erosions on skin & mucous membranes
- Oral lesions presenting sign in 60%
- Groin, face, scalp, neck, axillae common
Dx
- Nikolsky sign: slight pressure makes spidermis shear off
- Asboe-Hansen sign: gentle pressure on intact blister will force fluid under adjacent skin away from pressure site
Histopath
- Intraepidermal blister w/ 'tombstoning' effect
- Acantholysis
- DIF: intercellular IgG in epidermis (Chicken-wire pattern)
Rx
- Immunosuppressives: prednisone, azathioprine, mycophenolate mofetil, methotrexate, cyclosporine, IVIG, Rituximab |
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Term
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Definition
- Subepidermal blistering disorder
- IgG Abs to basement membrane
- Avg age of onset 65-75 yo
Dx
- Tense bullae, erythematous patches and urticarial plaques
- Pruritic
- Predilection for groin, axillae and flexor surfaces of forearms
- Bullae rupture & heal spontaneously
- Rare mucosal involvement
Histopath
- Subepidermal blister
- DIF for linear deposits of IgG & C3 @ basement membrane zone
Rx
- Topical or systemic steroids
- Tetracycline and Nicotinamide QID
- Resistant cases can use other steroid sparing immunosuppressives
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Term
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Definition
- Chronic, relapsing severely pruritic blistering disease
- Genetics - HLA-B8
- Associated w/ gluten enteropathy
Dx
- Grouped, bilaterally symmatrical papulo vesicular lesions
- Scalp, neck, axillary folds, sacrum & buttocks, elbows & knees
- Intense paroxysmal itching & burning
- IIF negative in Serum
Histopath
- Accumulation of Neutrophils, eosinophils & fibrin @ tips of dermal papillae -> microabscesses
- Multiloculated microabscesses become a subepidermal blister
- DIF: granular deposits of IgA @ tips of dermal papillae
Rx
- Dapsone
- Gluten-free diet |
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