Common causes of red, swollen and itchy feet include insect bite dermatitis, contact dermatitis and eczema. 1. Insect bite dermatitis: an allergic reaction to insect bites. If the top of the foot is bitten by mosquitoes, it will make a small amount of venom injected into the local deep tissue, so that the bite appeared in the red air bubble-like damage, manifested as redness, swelling, blisters and accompanied by itchy symptoms, you can follow the doctor’s instructions to apply glycerine lotion to stop the itching. 2. Contact dermatitis: usually due to skin and mucous membrane contact with certain exogenous substances, mostly seen in acute contact dermatitis. Its main symptom is itching, and can be manifested as lesions in the erythema, followed by swelling, blisters, papules and other manifestations, so it will also cause redness, swelling and itching on the surface of the feet, can follow the doctor’s instructions oral loratadine and other medications. 3. Eczema: can be caused by a variety of internal and external factors, such as long-term in the high temperature, humid environment, can be manifested as itching of the affected skin, especially in the acute stage can appear in the lesion parts of the local redness and swelling, or even erosion, oozing, etc., so it will also cause the top of the foot red, swollen and itchy situation. In conclusion, if the top of the foot is red, swollen and itchy, it is recommended to go to a regular hospital in time to get a clear diagnosis and targeted treatment.