Red rash on the root of the leg may be caused by ringworm, eczema and other diseases, which can be improved by general treatment and medication. 1. Ringworm: If the red rash at the root of the leg is caused by ringworm, patients need to keep the local clean and dry. You can follow the doctor’s instructions to use topical ketoconazole, econazole and other antifungal drugs, which have antibacterial and antiseptic effects. 2. Eczema: Eczema may also lead to a red rash on the root of the leg, patients should avoid scratching, excessive cleaning of the affected area. You can follow the doctor’s instructions to use topical hydrocortisone, halometasone, mometasone furoate and other glucocorticoid drugs, to play anti-inflammatory, anti-allergic effect. If a red rash appears on the root of the thigh, it is recommended to go to a regular hospital for examination, and cooperate with the doctor to standardize the treatment.