Sean Klepper M.D.
Stephen Lyle, M.D., ...
- A disease of the elderly characterized by large flaccid bullae on the face, scalp, chest, intertriginous areas and oral mucosa.
- Mediated by IgG antibodies directed against desmoglein 3, a component of desmosomes that is found in the greatest concentration between the keratinocytes of the lower epidermis.
- In the majority of patients, circulating autoantibody can be demonstrated using indirect immunofluorescence, with level roughly correlating with disease activity.
- Early lesions typically show only spongiotic dermatitis or occasionally eosinophilic spongiosis.
- Fully developed lesions show:
- Acantholysis with intercellular clefts progressing to suprabasilar blister formation (the basal layer of keratinocytes remains attached to the demis and is said to resemble a "row of tombstones"); sometimes the acantholysis extends higher into the epidermis
- The acantholytic keratinocytes are enlarged with glassy eosinophilic cytoplasm, nucleomegaly and prominent nucleoli.
- The acantholysis tends to involve skin appendages.
- Upper dermal perivascular lymphohistiocytic infiltrate
- Dermal edema
- The rete ridges may become elongated, giving rise to "villi": projections of the dermis (covered by the basal layer of keratinocytes) into the blister.
- Some cases display neutrophilic spongiosis.
- Neutrophils are also present when the lesions ulcerate.
- In later lesions there may be necrosis of the blister roof, as well as several layers (instead of the more typical single layer) of keratinocytes in the floor of the blister secondary to keratinocyte proliferation.
- Direct (and often indirect) immunofluorescence shows intercellular IgG, most prominent directly above the basal layer, in contrast to pemphigus foliaceus in which the immunofluorescence is concentrated in the superficial stratum spinosum. C3 is also positive in up to half of cases.