Category Archives: Skin

Information and news on skin diseases and skin conditions.

Linear IgA Disease

Linear IgA Disease

Clinical features: children or adults with pruritic bullae throughout, associated drug sensitivity

Skin lesion appearance: erythematous base

Histology: identical to dermatitis herpetiformis

Immunofluorescence: linear IgA at basement membrane not dermal papillae

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Transient acantholytic dyskeratosis

Transient acantholytic dyskeratosis

-    Spongiotic dermatitis
-    Hailey-Hailey
-    Darier’s
-    Pemphigus vulgaris

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Epidermolysis Bullosa

Epidermolysis Bullosa

Clinical features: > greater than 12 genetic disorders
- blisters form shortly after birth
- hands, elbows, knees

Histology:

- subepidermal blister; superficial dermis is fibrotic
- little to no inflammation

Immunofluorescence:

- linear deposits on epidermal-dermal basement – IgG and Complement C3

Electron microscopy: for classification

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Dermatitis Herpetiformis Histology

Dermatitis Herpetiformis Histology

Cause: autoimmune

Clinical features:

- young adults, associated with celiac disease, on extensor surfaces (“extends from skin to small bowel with celiac disease”), intensely pruritic

- anti-endomyseal, anti-gliadin, anti-transglutaminase antibodies
- HLA DR3, B8

Gross appearance: uriticarial plaques and vesicles

Histology:
- no acantholysis
- sub-epidermal blister with fibrin and neutrophils,eosinophils at tips of papillae “microabscesses and vacuolization”
- can spread along epidermal-dermal junction
fibrin

Immunofluorescence: granular deposits at tips of dermal papillae, IgA

Treatment:  gluten-free diet

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Bullous Pemphigoid

Bullous Pemphigoid

Cause: autoimmune

Clinical appearance: elderly, flexor surfaces

Gross appearance: tense bullae that do not rupture easily since bullae are below epidermis
- ? no acantholysis
- ? sub-epidermal blister with fibrin
- ? PVLI w/ ef + nf

Immunofluorescence:

- linear at epidermal-dermal junction

- IgG and complement C3 (bind to hemidesmosomes)

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Darier’s Disease

Darier’s Disease

Clinical appearance: neck and trunk

Gross: symmetrical distribution of red-brown keratotic papules

Histology

- suprabasal clefts, dyskeratotic, basophilic cells with large nuclei and a paranuclear halo (grains or corps ronds (granular layer and stratum))
- acanthosis and papillomatosis

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Impetigo

Impetigo

Cause: kids and adults: Staphylococcus aureus ? toxins A and B, which target desmoglein-1
- Streptococcal variant associated with SSSS

Gross appearance: crusted pustules

Histology

- subcorneal bulla with neutrophils beneath stratum corneum, “subcorneal pustule” ; roof of pustule is parakeratotic stratum corneum
Histochemistry

- Gram + for bacteria

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Pemphigus Vulgaris

Pemphigus Vulgaris

Cause: antibodies directed against demosomes protein, desmoglein-3

Clinical presentation: oral and skin

Gross: bulla, blisters→rupture easily because not below epidermis

Microscopy:

▪ acantholysis → cells become rounded
▪ “tombstones” → (i.e. “vulgar”)

Immunofluorescence

- fishnet pattern → IgG and C3 in lesional and non-lesional skin

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Pemphigus Foliaceous

Pemphigus Foliaceous

- subcorneal blister
- involves granulosa cell layer (see content for pemphigus vulgaris)

- antibodies against desmoglein-1

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Bullous diseases

Bullous diseases

1. Subcorneal
- Pemphigus foliaceous
- Staphylococcal scalded skin syndrome
- Impetigo

2. Suprabasal
- Pemphigus vulgaris
- Darier’s disease

3. Subepidermal
- Bullous pemphigoid
- Dermatitis herpetiformis
- linear IgA dermatosis
- epidermolysis bullosa

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