The thing that helped me a lot for dry skin is a high dose omega 3 supplement. Obviously talk to you doctor first to rule out the other medical causes but 750mg of DHA in a liquid supplement has made my skin (and allergies among other things) much better.
Good luck
Hi, welcome to the forum, Causes for dry skin are Sjögren's syndrome (also presents with dry mouth, cheek swelling), Mucin deficiency, Amyloidosis, Sarcoidosis, HIV infection and uncontrolled diabetes mellitus.
Hence, you need to undergo blood sugar, salivary mucin content etc. to rule out the cause. You need to use moisturizing cream on the skin, drink adequate fluids and drugs like low dose steroids will be helpful for above mentioned conditions.
You can use thick creams (eg, Eucerin, Cetaphil, Nutraderm), which have a low water content, or ointments (eg, petroleum jelly, Aquaphor, Petrolatum), which have zero water content, will be quite effective. I suggest you to consult physician for evaluation. Take care and regards.