Wrong statement is –
Koilonychia is seen in iron deficiency anemia (not in megaloblastic anemia).
Mees line is seen in Arsenic poisoning.
Pterygium is diagnostic for lichen planus.
Psoriasis can cause onycholysis
Mees line in arsenic poisoning
Pterygium of nails in Lichen planus
Onycholysis in Psoriasis
Koilonychia in Megaloblastic Anemia (B12 def)