A few home remedies that may help to alleviate the rash, and provide relief from the itching and burning sensation are as follows. » Prepare a smooth paste using 2 tbsp. cornstarch and water, and apply it on the rash. Allow it to dry for 30 minutes, and rinse off with cold water.tchy rash on stomach may be a simple skin irritation due to a particular garment, or may be a manifestation of a serious infection. Nonetheless, proper medical intervention at the earliest is necessary to understand the precise cause, and ensure appropriate treatment.