Itching in the groin region can be due to excess sweating (hyperhydrosis), fungal infections, acanthosis nigricans, dandruff, hydradenitis supparativa, heat rash
In all the above mentioned causes, hyperhydrosis and fungal infections are more common. Have you ever used antifungal treatments? Tinea cruris or jock itch is the common fungal infection that affects the skin of your inner thighs, buttocks and genitals. It causes an itchy red, ring shaped rash in these areas.