Lacy White lesions in the mouth with pterygium is seen in:
Purple polygonal papules marked by severe pruritus; lacy white markings called as Wickam's Striae, especially associated with mucous membrane lesions & pterygium are diagnostic of Lichen planus.
Psoriasis
P. Alba
Lichen planus
Leprosy
Lichen planus and Other papulosquamous disorders