The other possibility which can present with nail pitting as well thick,
white, silvery, or red patches of
skin is psoriasis. It
is thought that psoriasis occurs when the immune system overreacts, causing inflammation and flaking of skin.
My sincere advice is to consult a dermatologist and get these two possibilities probed. Blood tests and biopsy skin can help in confirming the diagnosis.
I would suggest you to consult a dermatologist and get steroids prescribed.