Dear Mike,
Seeing a dermatologist should be your first step. He/she can give you an exam to perhaps identify the cause of the itching and offer a better cream or ointment for you. You mentioned you've tried creams and ointments before. Over-the-counter hydrocortisone cream should provide the best relief for you outside of a stronger prescription cream from your doctor.
Other than that, it might just be a process of elimination to determine the cause. You could have some type of allergy or sensitivity to a soap you are using or to a laundry detergent. I know you said you use dye-free soaps and detergents, however they could still be the culprit. I've found the best laundry detergent for my son's sensitive skin to be Arm & Hammer Laundry Detergent for Sensitive Skin.
Even being hot and sweating can cause the itching. Gold Bond Medicated Powder would be a really good choice if sweating is an issue. It soothes the itching and protects the skin from rashes and breakdowns associated with heat rash and sweating. It helps relieve itching due to prickly heat rash.
Another cause could be DRY skin. A daily moisturizer for sensitive skin may provide relief. You don't need to spend a lot of money on those high priced fancy lotions. Lubriderm Sensitive Skin Therapy Moisturizing Lotion is a moderately priced lotion that works really well for dry skin. When choosing a lotion, look for a fragrance and dye-free lotion that is water based and pH balanced. Keri Sensitive Skin Therapy Moisturizing Lotion is another good one. Try to avoid allowing extremely HOT water from hitting you on the buttocks while in the shower to prevent irritation and drying.
If these things do not work for you; I hope you'll try to see a dermatologist. There is really nothing odd about your itching and no need to be embarrassed....honest.
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