Bullous pemphigoid
Early
| 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 |