Boils are skin infections that begin in the hair follicles. Because the whole body is covered in hair, boils can form almost anywhere, though they are most common in exposed areas. When the infection first develops, the skin turns red, followed by a lump. After four to seven days, pus collecting in the lump makes it turn white. There are many causes of boils, ranging from mild to severe.

Staphylococcal Bacteria

The vast majority of boils are caused by the staphylococcal bacteria, perhaps better known as a staph infection. Everyone has the staph bacteria on their skin, but it can only travel below the surface through a nick or cut, or by traveling down the hair to the follicle. Small boils are treated home with warm compresses, while larger boils may require a small incision and drainage, and antibiotics.

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Having Boils in the Past

Anyone who has had boils in the past is more likely to have a recurrent infection sometime over the next year. Additionally, individuals with diabetes, autoimmune conditions, or those who receive chemotherapy are more likely to experience recurring skin infections like boils. If the growths continue to reappear, they need to be examined by a doctor.



People with eczema or those with psoriasis or a similar skin condition are more likely to develop boils because skin inflammation and irritation allow the bacteria to move deeper into the skin tissue. This access also means the boils can become more severe. Proper treatment of skin irritations is key to preventing boils from becoming a persistent issue. A dermatologist can help diagnose and treat chronic skin conditions.



Folliculitis describes the inflammation of hair follicles. Often, infection follows or causes inflammation, leading to boils in the affected area. When this occurs, the person may notice numerous small red and pink bumps at the hair follicles. Folliculitis is often the result of friction from clothing, skin wounds, hot tub exposure, shaving or constant sweating.


Iron Deficiency Anemia

While anemia alone does not cause boils, it does make the body more susceptible to infection. As a result, boils are more likely to develop over small nicks or cuts. Iron-deficiency anemia can be mild or serious and should be treated by a medical professional. Symptoms of iron deficiency anemia include fatigue, fainting, chronic headaches, and general weakness.

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Diabetes suppresses the immune system, which leads to a higher chance of developing infections that cause boils. The disease also makes it difficult for the body to fight off infection, including those that occur on the skin. For this reason, people with diabetes who develop boils may need medical treatment to ensure the bacteria do not spread.


Ingrown Hairs

An ingrown hair can cause a boil to form if the follicle becomes infected. This can occur in any area of the body that has hair, including the genitals and face. In most cases, ingrown hairs that are promptly removed or treated will not lead to boils. Proper exfoliation and cleaning can prevent boils from developing due to ingrown hairs.



If a splinter is not removed right away, a boil may grow around the entry point in the following days. Bacteria can get into the skin via this point and fester inside, along with the splinter. Prompt removal of a splinter or regular application of antibacterial cream can help prevent the site from becoming infected.


Are Boils Contagious?

Though boils are not contagious, the bacteria that cause them could be. Therefore, if a boil is active and draining, it is best to keep it covered by a bandage at all times and to ensure the hands are washed regularly. The drainage from the infection can spread on the body, creating more boils, and pass to other people via personal shared items such as hand towels.

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Signs of a Severe Infection in a Boil

While knowing the causes of a boil is important, it is vital to recognize when the infection has become severe. Painful, swollen, or red skin around a boil should prompt an individual to seek medical attention. Other signs of a severe infection include more boils growing around the first one, the development of a fever, or swollen lymph nodes near the boil site.

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