In-shoe biaxial shear force measurement: the Kent shear system

Involvement of the nail unit in pemphigus vulgaris is thought to be uncommon. However, trachyonychia, nail atrophy, onychomadesis, onycholysis, nail bed erosion, onychoschizia, subungual haemorrhage, nail pitting, nail plate discoloration, cross-ridging of nail plate, Beau's line and paronychia have been reported. These manifestations may be due either to secondary extension of the bulla adjacent to the nail or primary involvement of the nail bed, nail matrix and nail fold. We report four patients with pemphigus vulgaris who developed paronychia with a corresponding exacerbation of their cutaneous lesions. Nail fold biopsy and direct immunofluorescence revealed features of permphigus vulgaris. Treatment with immunosuppressive agents showed simultaneous improvement of both cutaneous and nail lesions.