The bacterial skin disease, Boils is caused for several reasons. Generally the people having immune system disorders, diabetes, poor hygiene or malnutrition (Vitamin A or E deficiency) are more susceptible to developing boils, than others. However, boils can occur in healthy, hygienic individuals, as well; mainly due to over scratching a particular area of the skin.

An ingrown hair can cause boils in human body. The ingrown hair is prone to bacterial infection. Some types of boils can be caused as a result of a splinter or other foreign materials that have become inhabited in the skin. The plugged sweat glands that become infected are another cause behind developing boils. Any break in the skin, like a cut or scrape, can develop into an abscess, as well; if it becomes infected with bacteria. Some of the other causes of boils include wearing clothes that are too tight, or using immune-suppressing medications like corticosteroids. Apart from these, eye infection, or diabetes are also considered as possible reasons for causing boils.

A type of bacteria, the Staph bacteria (scientifically known as Staphylococcus aureus) is known as one of the main causes of boils. The bacteria infect one or more hair follicles and initiate the process of developing boils. Staph bacteria are often considered as harmless and they reside on the skin. Many people carry the germ in their nasal passages. The bacteria give rise to boils by penetrating the skin via a cut, scratch, break in the skin, or even through the sweat glands. Once the Staph bacteria enter the skin, the immune system of the patient releases an army of specialised white blood cells known as neutrophils to the location of entry to fight the infection. As a result of this, the skin inflames into a boil and the boil eventually gets filled with pus that contains old white blood cells, dead skin cells, and bacteria.

In the recent times, a virulent strain of Staph bacteria, named Methicillin-Resistant Staphylococcus Aureas (MRSA), has been identified as a cause to many skin infections, including boils. The MRSA causes recurrent skin boils and is resistant to many antibiotics. Apart from the Staph bacteria, a toxic condition in the blood stream is also another major cause for developing boils. Unhealthy lifestyle, or a poor diet is the main causes behind a person`s blood becoming toxic.