Itchy skin on both legs may be caused by allergy, infection, eczema and other reasons. 1. Allergy: patients may be exposed to allergens leading to allergic reactions, such as drugs, dust, mosquito saliva, etc. Allergic reactions are prone to red rashes, itching and so on. 2. Infection: Infection including mold, virus or bacteria may lead to itchy skin on both legs. 3. Eczema: Eczema is often characterized by pimples, papules, itching, redness, swelling, oozing and so on. Eczema is a common cause of itchy skin. Patients with itchy skin on both legs should go to the dermatology department in time for examination, to clarify the cause of the disease, and under the guidance of the doctor for treatment.