Bullous pemphigoid


Superficial perivascular and interstitial infiltrate of lymphocytes and eosinophils
Eosinophils scattered throughout the upper part of the reticular dermis, within the edematous papillary dermis and along the dermoepidermal junction
Eosinophils often within the epidermis, as solitary units mostly, but sometimes in tiny collections, in concert with spongiosis

Fully developed (vesicular)

Superficial and sometimes deep perivascular and interstitial infiltrate of lymphocytes and many eosinophils
Numerous eosinophils throughout the edematous upper part of the dermis
Subepidermal blister within which eosinophils are usually present and dermal papillae are often preserved
Spongiosis in company with eosinophils to the sides of the blister often

Late (bullous)

All the changes seen in fully developed lesions, with the addition sometimes of spongiotic vesicles and edema of the papillary dermis so marked that it verges on subepidermal vesiculation
Reepithelialization from adnexal epithelium in some lesions