milcu powder is fine.and it is really cheap too.maybe you can find it on ebay or amazon.jt is also dual purpose, where it can also be used as foot deo.it's alcohol and fragrance free than lessens the possibility of irritations.
DErmadoctor Total nonscents Ultra-Gentle Antipersp is among of the best antiperspirant that doesn't itch. Other best antiperspirants are The Rock, Deodorant Stones, Tom's of Maine and Crystal deodorant among many others.
Try washing the area more frequently, at least once a day, and apply a good antiperspirant deodorant once or twice daily. If the itch persists try switching brands . If it still persists see a Dr. It could be a medical issue