A white discoloration of the skin may occur for several reasons, including eczema, superficial yeast infection and skin conditions like psoriasis and vitiligo, according to Mayo Clinic. Dry white spots can also be caused by infections, allergies and autoimmune disorders, notes Lee Kaplan, MD.
Deficiencies in calcium, vitamin D and vitamin E may also lead to dry white patches. Eczema is a condition that causes dry itchy skin that may blister. It can be treated with hydrocortisone or antihistamines. Psoriasis is an autoimmune disorder that causes inflammation and can be treated with phototherapy or topical corticosteroids, according to Dr. Kaplan.