Hi itching in between testicles and anus can be fungal infection
which is due to uncleanliness or due to excessive moisture over the area.the itching all over the body can be acute urticaria
which is due to allergens like food.water or insect stings or drugs.
First one is treated with atarax
25 mg at night.terbinafine
250 mg daily once and application of sebafine ointment whereas second one is treated with atarax 25 mg at night and alaspan in the morning