Boils are pus-filled swellings in the skin surrounded by large inflammations.They may develop anywhere on the skin but are most likely to occur at the site of an infected hair follicle. Symptoms Irritation and itching and the person experiences pain when it occurs at site where there is lesser skin on the body.The boil bursts with a putrid discharge. Root causes May be caused by germs entering the sweat glands/hair follicles on the skin.Toxic impurities in the bloodstream may also cause boils.