For a definite diagnosis you would have to go to a dermatologist, who is a skin specialist, and whoshould be able to tell you what it is upon examination. You may have a type of eczema which is a very dry itchy skn condition. In the meantime you can treat the symptoms. Take a warm Aveno bath. You can buy Aveno oatmeal flakes in the drugstore. Ad them to bath water and soak in it. It will relieve the itching and calm the rash. After you towel dry, you can apply aloe vera gel, or hydrocortisone cream to the affected area. The areas that you get the rash are where your clothing fits a little closer. Where cotton clothing since it doesn't trap moisture and dress lightly.