Hello, Welcome to healthcare magic, If you get hives after bath it could be aquagenic urticaria, if it is just itching without hives, it could be aquagenic pruritus. Do not take bath in hot water. Use room temperature or luke warm water. Use very less soap. Oiling the body before bath is good and immediately after bath apply a moisturizing lotion all over the body. If your itching is not coming down in a week after following this regime, consult a dermatologist for prescription of oral anti histamines. Hope this helped, Take care.