Nail Lichen Planus in a Patient with Cogan Syndrome: Report of a Case and Discussion.

Cogan syndrome and lichen planus represent two autoimmune disorders. Cogan syndrome is a very rare type of ANCA-negative vasculitis affecting the eyes and vestibulocochlear system. It has been associated with other autoimmune disorders, none of them showing any lichenoid inflammation. We herein report the first case of a patient that suffered from Cogan disease and developed isolated lichen planus on all nails a few years after the first diagnosis. The combination of two autoimmune disorders is not unusual and raises the question of common immunogenetic pathomechanisms.