Pterygium of nail is seen in

Pterygium of nail Pterygium unguis results from a scarring involving the nail fold extending onto the matrix. "dorsal pterygium" where proximal nail fold fuses to matrix and later to nail bed "ventral pterygium" where a distal extension of the hyponychium attaches to the undersurface of the nail plate thereby obliterating the distal nail groove. Dorsal pterygium is classically seen in lichen planus. It may also be seen in burns, cicatricial pemphigoid, dyskeratosis congenital, graft versus host disease, radiodermatitis, and lupus erythematosus. ventral pterygium is seen in leprosy, neurofibromatosis, subungual exostosis, lupus erythematosus, and systemic sclerosis. IADVL Textbook of dermatology page 1075