Pemphigus foliaceous
There are many acantholytic cells in the upper epidermis. Some of these cells are dyskeratotic, as they often are in pemphigus. Pemphigus erythematosus has an identical appearance.
Clinically, pemphigus foliceous is dominated by scales and crusts and it may be difficult to find a vesicle to biopsy.
Darier's disease and Hailey-Hailey disease also show dyskeratotic acantholytic keratinocytes but the process begins in the lower epidermis with a suprabasal cleft. It can sometimes be surprisingly difficult to tell pemphigus vulgaris and Hailey-Hailey disease apart on biopsy but the clinical features are quite distinct: easily eroded flaccid, non-inflammatory vesicles and bullae are seen in pemphigus while Hailey-Hailey disease shows fissured, moist and macerated plaques in the flexures.
Pemphigus vulgaris, wrist
Hailey-Hailey disease, groin