Blisters are medically referred to as blisters. There are many reasons for blisters around the feet, such as excessive friction, fungal infection, viral infection, contact dermatitis and so on. 1. Excessive friction: wearing shoes that do not fit or localized external friction stimulation may cause blisters around the feet and other symptoms. 2. Fungal infection: blistering athlete’s foot caused by fungal infection can also cause blisters around the feet. 3. Viral infections: Herpes and other diseases caused by viral infections may also lead to blisters around the feet. 4. Contact dermatitis: allergic or irritant reactions occur after contact with certain sensitizing or irritating substances on the skin of the feet, resulting in erythema, papules, blisters, itching and other symptoms. Blisters on the side of the feet, there may be other reasons need to go to the hospital in time to check, follow the doctor’s instructions for treatment.