Hello. Thanks for writing to us at healthcaremagic It is extremely difficult to be absolutely sure about it without having had the opportunity to examine. I will have to keep a few possibilities: It could either be a fungal infection or it could be intertrigo (which is inflammation of the body folds). Sweat and occlusive clothing predisposing to both of these conditions. If it is bilateral, it is more likely to be one of these. A unilateral rash such as this, goes more in favor of Herpes Zoster, specially if it is sore and painful. Herpes Zoster later on forms fluid filled lesions and is characteristically located on one side of the body. Visual inspection would be the best way to determine the true nature of the rash and I would suggest that you visit a doctor for the needful. Regards