Hello dr i have problem with my skin it been itching especially my lower body my buttocks and between my legs, what could be the cause i need help?

STI? see Dr: Sexually transmitted infections can cause internal and external irritation resulting in itchiness. I would see a Dr to determine if there is an STI that can be treated. If you are not sexually active the alternative is a yeast infection that has spread to your buttocks and upper thighs. Either way, a Dr can examine you, determine the source of your discomfort and treat it.