There are several reasons for itching on the backs of both feet: 1. Most commonly, you have to look at whether there is a new change of shoes and socks. If this is indeed the case, you cannot rule out that it is caused by allergy to the newly changed shoes and socks, such as the fibers or pigments inside, that is, the added coloring causes skin allergy on the back of the feet, so it can cause itching. Allergic reactions to the back of the foot can have a rash, such as red spots, pimples, and small papules, and can be dense in patches, and this is caused by allergies.2. It cannot be ruled out that it is tinea pedis, which is often referred to as foot fungus. Foot fungus is caused by a fungal infection, and usually people who have other foot fungus in the house wear the same pair of shoes or wash their socks at the same time and may be infected with it. Tinea pedis occurs on the back of the foot or the center of the foot and the side of the ankle and causes redness, blisters, and significant itching, which is called tinea pedis. The treatment of tinea pedis is recommended to go to a dermatologist for fungal examination. If the fungal microscopy is positive for spores and hyphae, the diagnosis can be made clearly, and antifungal treatment with medications such as terbinafine, itraconazole, and ketoconazole can be administered.