A number of immunologically mediated skin diseases and immunologically mediated systemic disorders with cutaneous manifestations are now recognized as distinct entities with consistent clinical, histologic, and immunopathologic findings. Clinically, these disorders are characterized by morbidity (pain, pruritus, disfigurement) and, in some instances, result in death (largely due to loss of epidermal barrier function and/or secondary infection). The major features of the more common immunologically mediated skin diseases are summarized in this chapter (Table 55-1), as are autoimmune systemic disorders with cutaneous manifestations.
TABLE 55-1Immunologically Mediated Blistering Diseases ||Download (.pdf) TABLE 55-1 Immunologically Mediated Blistering Diseases
|Disease ||Clinical Manifestations ||Histology ||Immunopathology ||Autoantigensa |
|Pemphigus vulgaris ||Flaccid blisters, denuded skin, oromucosal lesions ||Acantholytic blister formed in suprabasal layer of epidermis ||Cell surface deposits of IgG on keratinocytes ||Dsg3 (plus Dsg1 in patients with skin involvement) |
|Pemphigus foliaceus ||Crusts and shallow erosions on scalp, central face, upper chest, and back ||Acantholytic blister formed in superficial layer of epidermis ||Cell surface deposits of IgG on keratinocytes ||Dsg1 |
|Paraneoplastic pemphigus ||Painful stomatitis with papulosquamous or lichenoid eruptions that may progress to blisters ||Acantholysis, keratinocyte necrosis, and vacuolar interface dermatitis ||Cell surface deposits of IgG and C3 on keratinocytes and (variably) similar immunoreactants in epidermal BMZ ||Plakin protein family members and desmosomal cadherins (see text for details) |
|Bullous pemphigoid ||Large tense blisters on flexor surfaces and trunk ||Subepidermal blister with eosinophil-rich infiltrate ||Linear band of IgG and/or C3 in epidermal BMZ ||BPAG1, BPAG2 |
|Pemphigoid gestationis ||Pruritic, urticarial plaques rimmed by vesicles and bullae on the trunk and extremities ||Teardrop-shaped, subepidermal blisters in dermal papillae; eosinophil-rich infiltrate ||Linear band of C3 in epidermal BMZ ||BPAG2 (plus BPAG1 in some patients) |
|Dermatitis herpetiformis ||Extremely pruritic small papules and vesicles on elbows, knees, buttocks, and posterior neck ||Subepidermal blister with neutrophils in dermal papillae ||Granular deposits of IgA in dermal papillae ||Epidermal transglutaminase |
|Linear IgA disease ||Pruritic small papules on extensor surfaces; occasionally larger, arciform blisters ||Subepidermal blister with neutrophil-rich infiltrate ||Linear band of IgA in epidermal BMZ ||BPAG2 (see text for specific details) |
|Epidermolysis bullosa acquisita ||Blisters, erosions, scars, and milia on sites exposed to trauma; widespread, inflammatory, tense blisters may be seen initially ||Subepidermal blister that may or may not include a leukocytic infiltrate ||Linear band of IgG and/or C3 in epidermal BMZ ||Type VII collagen |
|Mucous membrane pemphigoid ||Erosive and/or blistering lesions of mucous membranes and possibly the skin; scarring of some sites ||Subepidermal blister that may or may not include a leukocytic infiltrate ||Linear band of IgG, IgA, and/or C3 in epidermal BMZ ||BPAG2, laminin-332, or others |
AUTOIMMUNE CUTANEOUS DISEASES
Pemphigus refers to a group of autoantibody-mediated ...