The viral infection causes red vesicles to form on the skin. These contain fluids made up of toxins  produced by the virus that causes the itching sensation. You can use any any antiallergic prescribed by the doctor or try  the home remedies given in this article to get rid of the itch.
Note: The affected people should stay at home to prevent spreading the disease to others. You can cut the nails short or wear gloves to prevent scratching and minimize the risk of secondary infections. Apply Lactocalamine lotion to prevent burning sensation.