Subepidermal blister

Viable roof

Keratinocytes may become necrotic if the blister is old

Variable eosinophilic infiltrate

Subepidermal blister

Eosinophilic infiltrate

• Eosinophils are mononuclear; they have a very eosinophilic (pink-staining) cytoplasm and abundant cytoplasmic granules

Viable roof

Exocytosis of eosinophils — meaning eosinophils migrate upward into the epidermis

Dermal edema

Lymphocytes are also present within the inflammatory infiltrate rich in eosinophils, which is typical of eczematous pemphigoid

Spongiosis

Eosinophils can be identified by their deeply pink cytoplasm and abundant cytoplasmic granules