Those suffering from boils often wonder why they were targeted as these can be very painful. Knowing about the causes behind boils can help in selecting the right treatment to stop them. Unhealthy diet could be a cause behind boils so those suffering from boils due to it should restrict eating junk food and instead opt for fresh fruits and vegetables. Weakness of the immune system of the body is also a primary cause behind boils. As boils are also a kind of an infection, the weak immune system fails to protect the body from this infection and it results in frequent boils on the skin. Diabetics are more prone to infections like staph and fungal infections which later on take the shape of boils. Some medicines also affect the ability of the body to fight infections. Simple causes like wearing tight clothes or sitting in a same position for a long time can also cause boils.