There are a lot of over-the-counter products for body fungus. You might google "Jock Itch" and see if those symptoms sound familiar. At least in the U.S., you can get jock itch medication at any drugstore (in the UK it would be called a chemist).
First, try to determine if it is a foreign substance, such as a washing powder from the laundry when your underwear is washed, or a soap from when you bathe that is not visible until your body dries, or if it is something coming from you, such as salt when you sweat. It is an unlikely place for dandruff, but there are other things that come out of the body -- if you rule out salt from sweat (and don't rule it out until you taste the substance -- it might be precipitating in flakes) you might check to see if it is smegma (look it up online for a description) although that doesn't seem to be the most likely place. It doesn't sound like it would be from urine or a urinary tract infection, but who knows. Check to see if it is salty or soapy, and then check with your doctor.
it is not salt. it looks like white colur flakes.
No i am not using any powders. i just clean the area once when i take bath..
Hi are you using Talcum Powder to dry your private's ???
Are you sure it is not salt?