ABSTRACT
As nail psoriasis, nail lichen planus is a benign inflammatory disorder. when the nails are affected, however, it may lead to permanent destruction with severe functional and psychosocial consequences. When the inflammation is limited to the nail matrix, there is altered nail plate formation. Involvement of the proximal nail matrix gives rise to surface alterations, including thinning, fragility, longitudinal ridging, and fissuring. This longitudinal pattern is quite characteristic. In some cases, the matrix is only partially affected. Red spots in the lunula (mottled erythema) also correspond to focal distal matrix inflammation. In more severe cases, matrix involvement may result in marked thinning and shortening of the nail plate with anonychia. Dorsal pterygium is also a sign of severe focal nail matrix involvement with permanent destruction. Nail bed is less commonly affected and usually co-exists with nail matrix lichen planus. It is characterized by onycholysis with or without subungual hyperkeratosis. If the onycholysis is severe, the nail plate may be shed resulting in nail bed atrophy (disappearing nail bed syndrome) and permanent anonychia ( Figures 12.1 – 12.7 ).
