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What is Pterygium of the nail is seen in and explain in detail?
Pterygium of the nail is classically seen in lichen planus: Pterygium unguis (also known as "Dorsal pterygium") forms as a result of scarring between the proximal nailfold and matrix, with the classic example being lichen planus, though it has been repoed to occur as a result of sarcoidosis and Hansen's disease Ref Harrison 20th edition pg 1234