Hello. Thanks for writing to us at healthcaremagic Hyperpigmentation in the inner thigh region is most commonly because of recurrent fungal infections and is known as Post Inflammatory Hyperpigmentation(PIH). I would suggest that you visit a specialist for a confirmatory diagnosis whether it is due to underlying fungal infection. If that is the case, first of all fungal infection needs to be treated appropriately, with topical as well as Oral antifungals. Once the infection resolves, it is important to prevent a recurrence by using an antifungal dusting powder. PIH gradually lightens with time and if recurrence is prevented. Weight reduction in those who are overweight helps both with fungal infection as well as with resolution of dark patches. Regards