Cutaneous Bullous Diseases

Uploaded: 2007-11-25, Updated: 2007-11-25

Bullous Disease

Deposit

Location

Pattern

Antigen

Bullous Pemphigoid

IgG, C3

Basement membrane zone (BMZ)

linear band

BP230, BP180

Nikolsky −

Pemphigus Vulgaris

IgG > C3

Intraepidermis intercellular

Lace/chicken wire

Desmoglein 1, 3

Nikolsky +

Dermatitis Herpetiformis

IgA

Tip of dermal papillae, BMZ

Granular

Celiac disease

Linear IgA Dermatosis

IgA

 BMZ, not dermal papillae

Linear

LAD1

Bullous Pemphigoid

• A chronic, autoimmune, subepidermal, blistering skin disease that rarely involves mucous membranes.

• Primarily affects elderly individuals with an average age at onset of 65 years.

• IgG autoantibodies specific for the hemidesmosomal, an intracellular 230 kD protein (bullous pemphigoid antigen 1, BP230) and a transmembrane 180 kD protein (bullous pemphigoid antigen 2, BP180).

• DIF: IgG and C3 deposition, linear band, dermal-epidermal junction.

• Histology: Subepidermal blister, infiltration with polymorphous, eosinophil predominance. Mast cells and basophils may be prominent early in the disease course.

Pemphigus Vulgaris

• Most common type of pemphigus.

• An autoimmune, intraepithelial, blistering disease affecting the skin and mucous membranes mediated by circulating IgG autoantibodies directed against keratinocyte cell surfaces molecules, desmoglein 1 and desmoglein 3, especially the latter, a 130kD transmembrane glycoprotein located in desmosomes.

• Flaccid (soft and limp) blisters appear on healthy-looking skin and mucous membranes, especially in areas of pressure. These blisters form within the epidermis, high in the skin, and may be painful. Skin may be "peeled" off by rubbing a finger on it (Nikolsky sign).

• Histopathology: intradermal blisters. The earliest changes consist of intercellular edema with loss of intercellular attachments in the basal layer. Suprabasal epidermal cells separate from the basal cells to form clefts and blisters. Basal cells are separated from one another and stand like a row of tombstones on the floor of the blister, but they remain attached to the basement membrane. Blister cells contain some acantholytic cells.

• DIF: intercellular deposition of IgG on the surface of the keratinocytes throughout the epidermis. IgG1 and IgG4 are the most common subclasses. Complement components such as C3 and immunoglobulin M are present less frequently than IgG.

Dermatitis Herpetiformis

• Associated with a gluten-sensitive enteropathy (GSE).

• IgA endomysial antibodies. Associated with HLA-DQ2, DR3, B8.

• Grouped excoriations; erythematous, urticarial plaques; and papules with vesicles. These are located on the extensor surfaces of the elbows, knees, buttocks, and back. It is exquisitely pruritic, and the vesicles are often excoriated to erosions by the time of physical examination.

• Histology: Neutrophils in the dermal papillae, with fibrin deposition, neutrophil fragments, and edema. Eosinophils may be present. Papillary microabscesses form and progress to subepidermal vacuolization and vesicle formation. Vesicles form in the lamina lucida, the weakest portion of the dermoepidermal junction.

• DIF: Granular IgA prominently deposits in the tip of dermal papillae, also in BMZ.

Linear IgA Dermatosis

• Linear IgA dermatosis (LAD) is an autoimmune subepidermal vesiculobullous disease that may be idiopathic or drug-induced. Children and adults are affected, with disease of the former historically referred to as chronic bullous dermatosis of childhood.

• Antigen: most commonly a 97 kD component of the anchoring filaments, LAD1.

• Early urticarial papules or plaques reveal neutrophils aligned along the BMZ accompanied by vacuolar change. Neutrophilic microabscesses may be seen in dermal papillae. Fully developed lesions reveal subepidermal blistering with a predominantly polymorphonuclear infiltrate, although mononuclear cells and eosinophils may be present. Obtaining a frozen section of a blister roof may be helpful in some patients to rule out full-thickness epidermal necrosis as seen in toxic epidermal necrolysis.

• Linear deposition of IgA at the basement membrane zone.

REFERENCES

• Henry's Clinical Diagnosis and Management by Laboratory Methods. 21st edition.

• Essentials of Anatomic Pathology, Liang Cheng

• http://www.emedicine.com