You may have to experiment around to see what helps you. For me, I mixed tea tree oil with moisturiser and it uaually helps to soothe the itch. Grandpa's pine tar soup (from iherb) also helped. Keeping the area cool in general makes it more bearable. My doctor gave me zyrtec to take if you are ok to try it. There are also many other natural remedies that others have tried if you Google it. I know how unbearable it can get especially at night when you are trying to sleep. I hope you find something that helps you soon!
i had this rash suddenly too starting of 2nd trimester. try suubalm too soothe the itch, since its cooling. if really cannot take it then take cetirizine. i also use the snake brand powder all over.