What Is a Carbuncle?
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Medically reviewed by Marisa Garshick, MD
A carbuncle is a cluster of boils (furuncles) that form under the skin's surface when bacteria infect hair follicles (tiny openings on your skin through which hairs grow). Carbuncles appear as red, swollen, pus-filled bumps that most commonly develop on the back of the neck, back, armpits, and buttocks.
Staphylococcus aureus (staph) bacteria cause most carbuncles. Carbuncles can affect anyone, but older adults and people with obesity, weakened immune systems, or diabetes are more likely to develop them. Carbuncles can be painful, but most are treatable with home remedies. In some cases, a carbuncle may require medical treatment.
Carbuncle Symptoms
A carbuncle typically develops over several days. The affected area may be itchy before a lump appears under your skin. Carbuncles range in size—some are pea-sized, and some are as large as a golf ball. Carbuncle symptoms include:
Redness and swelling surrounding the lump under your skin
Tenderness or pain
A white or yellow-colored center (filled with pus)
Drainage or oozing of pus and blood if the carbuncle ruptures
A yellowish crust that forms in the area of the carbuncle after it ruptures and drains
Some people with a carbuncle also experience symptoms such as:
What Causes Carbuncles?
A carbuncle is a type of skin infection called an abscess. It develops when bacteria enter and infect two or more hair follicles, leading to a bacterial infection that spreads into deeper layers of your skin. Staphylococcus aureus (staph) bacteria cause most carbuncles, though methicillin-resistant Staphylococcus aureus (MRSA) and other bacteria are also known to cause carbuncles.
Staph bacteria live on your skin, inside your nose, and in the genital area of about 33% of people. They're usually harmless. A break in your skin from a cut, scratch, or puncture wound allows bacteria to enter and multiply, causing an infection. The bacteria spread and infect multiple hair follicles. Your immune system responds by sending infection-fighting white blood cells to the affected area, causing inflammation and the formation of a pus-filled carbuncle.
Risk Factors
Anyone can develop a carbuncle, but certain factors can increase your risk. These include:
Poor hygiene
Being immunocompromised (having a weakened immune system)
Underlying conditions, such as eczema, diabetes, alcohol use disorder, and obesity
Direct contact with a person who has a staph infection
Living in crowded conditions
Diagnosis
Diagnosing a carbuncle involves a physical examination by a healthcare provider. During the exam, your provider will look for the characteristic signs of a carbuncle, such as redness, swelling, and pus formation. Your provider may order tests to determine the type of bacteria causing the infection and develop a treatment plan.
Tests may include:
Bacterial culture: Using a special swab, your healthcare provider will gently collect a small pus sample from the carbuncle and send it to the lab to identify the type of bacteria causing the infection.
Blood test: Your healthcare provider may order a complete blood count (CBC) test to check for markers of infection (e.g., elevated white blood cell count) if they're concerned that the infection has spread to your bloodstream.
Carbuncle Treatment
Carbuncles are usually treated by primary care providers, family doctors, or dermatologists (doctors who specialize in skin, hair, and nails). Treatment focuses on clearing the infection and promoting healing. Treatment options for carbuncles vary depending on the severity of the infection and the location of the carbuncle.
Home Care
A carbuncle will often go away within two weeks with simple home care measures. It generally needs to drain to heal. You can help it drain by placing a warm, moist cloth on the carbuncle several times daily.
Do not attempt to pop, squeeze, scratch, or pick at a carbuncle. The bacteria that cause carbuncles are highly contagious and spread easily. You can take measures to prevent the spread of bacteria to other areas of your body and other people:
Wash your hands with soap and water after touching the carbuncle
Use clean towels and washcloths on your skin, and do not share them with others
Wash your clothing, bedding, towels, and other items that come into contact with the carbuncle
Change bandages often and dispose of them in a plastic bag
Antibiotics
If a carbuncle does not heal within two weeks, your healthcare provider will prescribe antibiotics to eliminate the infection. Healthcare providers also prescribe antibiotics for carbuncles on the face or spine or when you have signs of a systemic (whole-body) infection, such as fever and fatigue.
Antibiotics for treating carbuncles are generally oral medications (taken by mouth). Your healthcare provider may prescribe:
Sulfamethoxazole/trimethoprim
Clindamycin
Doxycycline
Minocycline
It is important to take antibiotics as prescribed and finish the entire course of medication to ensure the infection is completely cleared. This also lowers the risk of recurrence.
Your healthcare provider may also prescribe antiseptic soap (e.g., chlorhexidine gluconate with isopropyl alcohol or chloroxylenol) to cleanse the affected area or antibiotic ointment to apply on specific areas of your skin. This can help eliminate the bacteria causing the infection and prevent recurrent infections.
Incision and Drainage
Your healthcare provider may need to drain the abscess to promote healing and prevent the infection from spreading. This simple outpatient procedure—called incision and drainage—requires just a few steps. Your healthcare provider will:
Cleanse the area with an antiseptic
Numb the area with an anesthetic (numbing) injection or apply a numbing cream to minimize your discomfort
Make a small cut in the carbuncle with a scalpel blade and allow it to drain
Rinse the drained carbuncle with saline solution to remove any remaining pus or debris
Pack or bandage the area to protect exposed skin, promote healing, and prevent recurring infection
Prevention
Good hygiene and self-care practices can help lower your risk of developing a carbuncle. Here are some recommendations:
Maintain good hygiene: Wash your hands regularly with soap and water, especially after using the restroom, before eating or preparing food, and after spending time in public spaces. Shower or bathe regularly, especially after exercise or sweating.
Keep wounds clean and covered: Promptly clean and cover any cuts, scrapes, or insect bites with gauze or a sterile bandage to prevent bacteria from entering your skin.
Avoid sharing personal items: Don't share towels, washcloths, razors, or other items that come into contact with your skin.
Manage underlying conditions: If you have a weakened immune system or live with a chronic condition that increases the risk of carbuncles (e.g., diabetes), follow your treatment plan and see your healthcare provider regularly to manage the condition and prevent complications.
Complications
Most carbuncles heal with self-care and proper treatment. An untreated carbuncle can lead to complications, such as:
Sepsis: Sepsis (blood poisoning) is a bacterial blood infection that can develop if the bacteria spread from the skin to the bloodstream. Sepsis can be life-threatening, so seek immediate medical attention if you have a carbuncle and develop symptoms that suggest the infection is spreading, such as fever or fatigue.
Internal abscesses: Pus-filled pockets can develop in other body areas if the bacteria spread from the carbuncle to the bloodstream. Abscesses can form in the brain, spinal cord, or internal organs (e.g., kidneys).
Scarring: Carbuncles generally affect deeper layers of skin and can leave a permanent scar after healing.
A Quick Review
Carbuncles are clusters of boils that form a painful, red, and swollen lump under the skin. Staph bacteria cause most carbuncles. They can form anywhere on the skin but most commonly develop on the back, neck, buttocks, and armpits.
Some carbuncles clear up and heal with at-home measures, such as applying a warm compress several times daily. Don't attempt to pop, squeeze, scratch, or drain a carbuncle. This can worsen or spread the infection.
See a healthcare provider for treatment if you have a persistent carbuncle that does not heal within two weeks. Some carbuncles require antibiotics to clear the infection or an incision and drainage procedure to remove the carbuncle and promote healing.
Frequently Asked Questions
What is the difference between a carbuncle and an abscess?
A carbuncle is a type of skin abscess that forms when bacteria infect hair follicles through an open cut, scrape, or wound on the skin. An abscess can develop on any body part, including internal organs, but a carbuncle only develops on the skin.
What happens if you squeeze a carbuncle?
Squeezing a carbuncle can worsen the infection and spread the bacteria to surrounding tissues and other people.
Can a carbuncle go away on its own?
In some cases, a carbuncle can be removed with at-home measures, such as placing a warm, wet cloth over the affected area several times a day to encourage it to drain. If a carbuncle does not heal within two weeks, see a healthcare provider to discuss treatment options.
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