Hi Thanks for the query. As per your complain itchiness over the roof of the mouth can be secondary to infection in throat or it can also be due to allergic reaction to any food or medicine. Brown patches over the palate can be due to excessive melanin formation and is commonly seen in smokers causing smokers melanosis or can be melanoplakia. A confirmation of cause can be done only after a thorough clinical evaluation and investigations if needed like Biopsy to rule out the exact cause and can be treated accordingly. As of now you can take anti-histamines like Levocetrizine to relieve itching and avoid smoking if you are a smoker. Drink plenty of water and avoid hot and spicy food Hope this helps Regards