Suggest Medicine For Small Boils On The Leg

Sir my dad is 46 yrs old. for many years he has been suffering from allergic problems. from last one year and so the problem has aggrevated more. A small spot like thing comes in his legs. then it grows big from inside. usually the boils come out but in his case it goes inside. It lasts for around 15 days. he has been taking antibiotics like phexin. your suggestions please..after that infection heals it becomes like a wound mark.