Localized redness and itching on the back of the foot is an inflammatory skin injury, usually related to mosquito bites, eczema, and dermatitis symptoms. You can use boric acid or dehumidification and antipruritic solution, gauze after cleaning, local to wet compress. Three to five times a day, once for about fifteen minutes. After the wet compress, topical treatment with mometasone ointment, compound beclomethasone camphor cream and so on. If the effect of local medication is not very satisfactory, you can also take oral antihistamines, such as loratadine, cetirizine, etc., choose one of them, all have a better effect, generally three to five days can be effectively controlled.