Microscopic Nikolsky's sign.

Nikolsky's sign is a useful clinical sign in patients with active pemphigus. It does not however, indicate the level of split in the skin, and is seldom present in partially-treated patients. The purpose of this study was two fold: (i) to document the microscopic or subclinical counterpart of clinical Nikolsky's sign; and (ii) to improve the diagnostic yield of routine histopathology in pemphigus patients in whom the lesions are infected/old and are therefore not useful for histopathology, and when intact blisters are not present; this is particularly useful for institutions in which immunofluorescence facilities are not available. Pemphigus patients were allocated to one of two groups. Group A patients (n = 23) were subjected to manual tangential pressure over the perilesional skin before a biopsy specimen was taken from that site; group B patients (n = 14) were subjected to a biopsy without the tangential pressure technique. Group C consisted of 37 healthy volunteers who were subjected to the tangential pressure technique before a biopsy. Histopathological changes of pemphigus vulgaris or foliaceus were present in 73.9% patients in group A, 28.6% in group B and none in the control group C. Tangential pressure as described below can produce microscopic changes in the epidermis which are diagnostic of pemphigus. These changes are produced at the suprabasal level in pemphigus vulgaris and intraepidermally in pemphigus foliaceus. This technique is of value in those parts of the world where immunofluorescence facilities are not readily available.