Diagnosis:
Vesiculobullous Diseases
• A subepidermal blister with neutrophils can be found in the lesions of dermatitis herpetiformis, bullous systemic lupus erythematosus, linear IgA dermatosis, chronic bullous disease of childhood, and the inflammatory type of epidermolysis bullosa acquisita.
• Dermatitis herpetiformis is a rare, chronic, subepidermal blistering disorder characterized by a symmetric distribution of intensely pruritic papules and vesicles on the extensor surfaces of elbows, knees, shoulders, nape of neck, and sacrum. The histopathologic appearance is characterized by collections of neutrophils at the tips of dermal papillae, resulting in papillary microabscesses. Direct immunofluorescence reveals granular deposition of IgA at the dermal-epidermal junction and in tips of the dermal papillae.
• Histologically, bullous systemic lupus erythematosus resembles dermatitis herpetiformis, with subepidermal splitting and papillary neutrophilic microabscesses. However, direct immunofluorescence reveals linear or granular deposits of IgG and C3 along the basement membrane zone. IgA, IgM, or both also may be present. The immunoreactants are deposited beneath the lamina densa owing to the presence of autoantibodies to type VII collagen, and they are accordingly on the dermal side of a salt-split skin specimen.
• Adult linear IgA bullous dermatosis and chronic bullous dermatosis of childhood are regarded as different clinical manifestations of the same disease. They demonstrate similar histopathologic appearance, with subepidermal blister formation and a predominant neutrophilic infiltrate. The histologic appearance may seem to be identical to dermatitis herpetiformis, although lesions of linear IgA bullous dermatosis have less of a tendency to form papillary microabscesses. Direct immunofluorescence in linear IgA bullous dermatosis and chronic bullous dermatosis of childhood reveals homogeneous linear IgA deposition along the basement membrane.
• The heterogeneous group of subepidermal blisters with little inflammation (“cell-poor” subepidermal blisters) includes some variants of epidermolysis bullosa, porphyria cutanea tarda, cell-poor type of bullous pemphigoid, burns, toxic epidermal necrolysis, suction blisters, diabetic bullae, bullous amyloid, and some bullous drug reactions.
Mutasim DF, Adams BB:
Immunofluorescence in dermatology. J Am Acad Dermatol 2001;45(6):803-822; quiz 822-824.
Wojnarowska F, Bhogal BS, Black MM:
Chronic bullous disease of childhood and linear IgA disease of adults are IgA1-mediated diseases. Br J Dermatol 1994;131(2):201-204.