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What causes boil? 6 possible conditions

What Is a Furuncle?

Furuncle is another word for “boil.” A boil is a bacterial or fungal infection of a hair follicle. The infected hair follicle can be on any part of your body—it is not limited to your scalp. When the hair follicle becomes infected, the skin around it also becomes inflamed. The furuncle looks like a red, raised bump on your skin, but can later rupture and weep fluid.

Furuncles are most commonly found on the face and neck. You might also develop a boil on your thigh or buttocks.

What Causes Furuncles?

Any type of bacteria or fungi can cause a furuncle. The most common cause is a bacterium called Staphylococcus aureus. You might also refer to a boil as a staph infection. Everyone has Staphylococcus aureus on their skin as a normal occurrence. The bacterium causes an infection only if it enters your bloodstream through an open wound, such as a cut or a scratch. Once the bacterium is in your blood, your immune system tries to fight it. The boil is actually the result of your white blood cells working to eliminate the infection.

You are more likely to develop a boil if your immune system is compromised, or if you have a medical condition that causes wounds to heal more slowly. Diabetes and eczema (a chronic skin disorder characterized by extremely dry, itchy skin) are two examples of chronic conditions that may increase your risk of getting furuncles. Your risk can also increase if you engage in close, personal contact with someone who already has a staph infection.

Symptoms of a Furuncle

A furuncle may begin as a benign-looking bump on your skin, similar to a pimple. As the infection worsens, however, the boil can become painful and hard. Bacteria and dead skin cells may then build up underneath the skin, forming pus. The pressure from this accumulation of debris builds, which may cause the furuncle to erupt and release its fluids.

The pain is usually at its worst right before a furuncle ruptures and will most likely improve after the boil drains.

According to the Mayo Clinic, furuncles range in size from as small as a pea to as big as a golf ball (Mayo, 2010). The skin around the infected hair follicle may become red, swollen, and tender. Scarring is also possible.

The development of several boils in the same general area of your body is called a carbuncle. Carbuncles may cause a fever and chills. These symptoms are less common with a single boil.

Treating Furuncles

Many people do not need to see a doctor for treatment unless a boil remains large, unruptured, or very painful for more than two weeks (NIH, 2010). Usually within this timeframe, a furuncle will already have drained and begun to heal.

Treatment for stubborn furuncles generally includes steps to promote drainage and healing. Warm compresses can help speed the rupturing of a furuncle. Apply a warm, moist compress throughout the day to facilitate drainage.

Continue to apply warmth to provide both healing and pain relief after a boil has ruptured. Wash your hands and the boil site thoroughly and frequently with warm water and antibacterial soap to avoid spreading the staph bacteria to other areas of your body.

Contact your doctor if your furuncle remains unruptured or if you are in severe pain after a couple of weeks. You may need antibiotics to clear the infection. Your doctor may also elect to manually drain the boil with sterile instruments in his or her office. Do not try to open it yourself by squeezing, pricking, or cutting. This can increase your risk of deeper infection and more severe scarring.

Complications from Furuncles

The majority of furuncles heal without medical intervention or complications. In rare cases, boils can lead to more complicated and dangerous medical conditions. Blood poisoning is an infection of the bloodstream that may occur after having a furuncle. This type of infection, called sepsis, can lead to infections of the heart’s lining or the brain.

Another possible complication associated with boils is the development of an infection called MRSA. MRSA is an abbreviation of Methicillin-resistant Staphylococcus aureus.

Standard antibiotics to treat furuncles and other types of infection are not able to eliminate MRSA. Your doctor will most likely prescribe a different kind of antibiotic called vancomycin if you develop this more serious infection.

Prevent furuncles through good personal hygiene. Wash your hands often, clean all open wounds, and keep wounds covered with bandages. Avoid contact with those infected with staph or MRSA.

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See a list of possible causes in order from the most common to the least.


MRSA (Staph) Infection

MRSA (methicillin-resistant Staphylococcus) is a type of contagious bacterial infection that is resistant to beta-lactam antibiotics. CA-MRSA typically causes lesions that are red, swollen, and painful to touch.

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Diabetes Overview

Diabetes is a group of chronic metabolic diseases caused by defects in insulin production or function. Advanced diabetes may cause stomach pain, nausea, dizziness, and cramps.

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Immunodeficiency Disorders

An immunodeficiency disorder is a condition that disrupts your body's ability to defend itself against infection and disease. It can be congenital or acquired.

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Eczema is a common skin condition caused by an overactive immune system. It is marked by itchy and inflamed patches of skin.

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Nutritional Deficiencies (Malnutrition)

A nutritional deficiency occurs when the body doesn't absorb the necessary amount of a nutrient. Deficiencies can lead to a variety of health problems.

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Smallpox is an extremely contagious and deadly virus for which there is no known cure. The last known case occurred in the U.S. in 1949 and due to worldwide vaccination programs, this disease has been completel...

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This feature is for informational purposes only and should not be used to diagnose.
Please consult a healthcare professional if you have health concerns.