S6C28P22-1: In this lesion of dermatitis herpetiformis, the defects at the dermal-epidermal interface are multifocal. The epidermis forming the roofs of the defects shows a loss of a defined basal layer (cytolysis?). The irregular acidophilia of the epidermis might also be cited as evidence of damage - a degenerative change. In three of the separate defects, condensed fibrin blends with the affected dermal papillae; the interface between the two components is poorly defined. In part, some of the dermal changes may represent fibrinoid necrosis of connective tissue. Inflammatory cells in the fibrin have disintegrated; in the process, they have liberated basophilic nucleic acids into the exudate (a marker for the breakdown of inflammatory cells and for the release of digestive enzymes). The separate defects are unusually well-developed suprapapillary abscesses. The papillary dermis is edematous and inflamed. Eosinophils are present in the infiltrates.

S6C28P22-5: Smudgy fibrinoid and basophilic necrosis are present in the tip of this dermal papilla. There is a loose infiltrate of neutrophils; some of the cells show fragmentation of nuclei (leukocytoclasia). Some of the nuclear debris is present in the cytoplasm of a histiocyte to the left below the center of the field. Clearly, the papillitis of DH is something more than a mere collection of neutrophils in a defect at the tip of a dermal papilla; it is a necrotizing and suppurative papillitis.

S6C28P22-6: In the region of a “suprapapillary abscess,” the interface between exudate and papillary dermis is obscured by deposits of fibrin and by damage to connective tissue. To the left of the cleft, basal keratinocytes have been lysed by the release of enzymes and the effects of the inflammation. In addition, in this same area, but closer to the inferior portion of the field, basal keratinocytes are represented; they show cytoplasmic acidophilia and some coarsening of chromatin patterns. These cytologic changes are markers with which an observer can characterize the affected cells as being in the process of dying. The changes affecting basal keratinocytes are cytopathic.