<prompt> Pterygium of the nail is seen inLichen planusPsoriasisTinea unguiumAlopecia areata  <response>: 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 Hansens disease Ref Harrison 20th edition pg 1234 