Originally Posted by thickjohnny
Infection? What kind of infection could cause this without other indications?
A yeast infection, a bladder infection, some of the myriad STIs. Some people can be completely asymptomatic for a long time, while others have only a handful of symptoms. Seeing as this has cropped up while everything else is going on normal for the OP, it's best to let a doctor investigate.
Of course, a change in diet may also be the culprit. Between sweat and urine, your crotch may have picked up a malingering odour, OP. Like the old story about people smelling like garlic after they eat lots of it, other foods can change your body odour.