Hello, You have developed a rash and itchy blisters on the bottom of the fractured foot. Your symptoms may be due to allergy. Air cast boots can cause red, itchy rashes on the feet, especially on the tops of the feet and toes. Allergy is caused due to leather glues or rubber glues used. Chemicals and fragrance additives used in the making of these boots can trigger allergy. You can take the boot off an hour before bedtime to give your skin some breathing room, you can get it cleaned gently, dry it and apply a thin layer of ointment hydrocortisone to prevent itching. You should put it back on before going to bed as you want your foot to remain safe and to prevent it from getting hurt. Keep your boot off every time you are resting and wear it when you have to walk. Fresh air and sunlight will do miracles for your recovery. Make sure that your air cast boot fits you well otherwise it will do more harm than good. Avoid too much walking, do not put the weight of your body on the affected foot. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K., General & Family Physician