Dark brown patches on the inner thighs can be treated by physical therapy as well as medication. Dark brown patches on the inner thighs may be caused by diseases such as coffee spots, seborrheic keratosis, and ringworm. 1. Coffee spot: the general cause of coffee is related to genetic factors, and also affected by sun exposure and systemic diseases, which will lead to skin pigmentation. It can be treated with laser and cryotherapy under the guidance of doctor. 2. Seborrheic keratosis: Seborrheic keratosis is related to the aging of the patient’s skin, heredity and strong sun exposure, which will cause the patient’s skin to appear rough and brown patches of different sizes. You can apply tazarotene cream, vita-acid cream and other medications, and patients with serious conditions can also be treated with laser and cryotherapy. 3. Ringworm: Ringworm is caused by fungal infections and is also associated with excessive sweating and wearing tight underwear, resulting in dark brown patches of skin and itching. It can be treated by applying tretinoin econazole cream and compound ketoconazole ointment, as well as oral itraconazole capsules and terbinafine hydrochloride tablets. Patients must follow the doctor’s instructions to use medication during treatment, and pay attention to skin cleaning, prohibit eating spicy food, so as not to affect the patient’s recovery.