Everything to Know About Boils on the Skin

Medically Reviewed By Madeline Knott, MD
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A boil, or a furuncle, is an infection involving a hair follicle on the skin. It happens when bacteria enter the skin. Boils are typically caused by Staphylococcus aureus bacteria, though they may be due to other bacteria or fungi present on the skin surface. If multiple boils occur, this is known as a carbuncle.

Read on to learn more about boils. This guide includes information about causes, symptoms, treatments, and more.

What does a boil look like?

View the slideshow below for pictures of boils.

boil-1.jpg

Boil

Photo: DermNet New Zealand

boils skin infection on my nephew due to dirty blood circulation and skin irritation

Boil

Francisco de Casa/Alamy Stock Photo

boil-10.jpg

Boil

Reproduced with permission from ©DermNet NZ www.dermnetnz.org 2022

boil-11.jpg

A boil with surrounding cellulitis

Reproduced with permission from ©DermNet NZ www.dermnetnz.org 2022

What causes a boil?

A woman is holding a towel against her neck.
Willie B. Thomas/Getty Images

Boils form when bacteria from the skin surface infiltrate a hair follicle, infecting the hair follicle and surrounding tissue. This can happen due to friction or bacteria entering the skin through a cut or graze.

Boils may form individually or group together. When multiple boils fuse to become one lump, the resulting lump is called a carbuncle. Learn more about carbuncles.

Boils may occur anywhere on the body, though they are most commonly located in the following places:

  • armpits
  • buttocks
  • groin
  • thighs
  • genitals
  • back

What are the symptoms of a boil?

A boil can develop within a few hours or a few days. Symptoms of a boil include:

  • a red or discolored lump or bump with a yellow center
  • a bump that is itchy or tender
  • swelling
  • leaking pus that is yellowish
  • redness or discoloration

If you develop a carbuncle, which is a cluster of boils, you may also experience symptoms such as:

Carbuncles are less common than boils.

Find out how to tell the difference between a boil and a pimple.

How do I treat a boil?

You may be able to treat a boil with home remedies. However, medical treatments may also be necessary if the boil does not respond to home remedies, if you have multiple boils, or if you have a boil and a medical condition such as diabetes.

Home remedies

Home remedies for treating a boil include:

  • cleaning the area with antibacterial or antiseptic soap
  • applying a washcloth soaked in warm water to the boil for around 10 minutes four times per day
  • protecting the area by covering it with a dressing
  • washing your hands regularly to prevent further infection

Medical treatments

Medical treatments for a boil can include:

  • taking over-the-counter pain medication, such as paracetamol or ibuprofen
  • applying an ointment called a “drawing salve” to draw out the pus
  • taking antibiotics if you are likely to develop a carbuncle
  • draining the pus in a sterile medical setting

It is important not to squeeze the boil yourself. Your doctor will make a small cut to drain the pus in a clinical environment. They will then disinfect the wound and apply gauze to the affected area to protect it while it heals.

Find out more about how to get rid of boils.

How can I prevent a boil?

You can take steps to prevent the likelihood that you will develop a boil. These steps include:

  • cleaning any cuts or grazes and keeping them covered
  • avoiding sharing towels and face cloths with other people
  • avoiding smoking, which may make you more likely to develop a boil
  • washing your hands with antiseptic hand rubs
  • eating a healthy, balanced diet

When should I contact a doctor?

You should contact a doctor if any of the following apply:

  • The boil is on your face, nose, or spine.
  • The area around the boil feels painful and hot.
  • The boil does not respond to treatment within 2 weeks.
  • You frequently get boils or have a cluster of boils, known as a carbuncle.
  • You have a long-term medical condition such as diabetes.
  • You experience symptoms such as shivering or feeling hot.

How do doctors diagnose a boil?

Your doctor may be able to diagnose a boil by taking a medical history and carrying out a physical examination.

If you frequently have boils, your doctor may arrange tests to determine the bacteria causing the infections. Possible tests can include blood tests and taking a swab of pus from the boil for laboratory analysis.

Confirming the type of bacteria can help your doctor determine the best kind of antibiotics for you.

What are the risk factors for a boil?

Certain risk factors make you more likely to get boils. These factors include:

What are the complications of a boil?

A boil occurs as a result of a bacterial infection. It is possible that this infection can spread, resulting in complications.

Possible complications of a boil include:

  • abscesses from large boils
  • carbuncles, which occur when multiple boils join together
  • cellulitis, which occurs when surrounding tissue becomes infected
  • lymphangitis, which occurs when the infection affects a lymph vessel
  • lymphadenitis, which occurs when lymph nodes become inflamed
  • furunculosis, which is when boils keep recurring or develop in multiple places
  • meningitis or blood clots if the bacteria from a face boil spread to the brain

In very rare cases, you may also develop blood poisoning, or sepsis. This can occur if a lot of bacteria enter the blood and spread to the rest of the body.

Boil vs. cyst: What is the difference?

A boil is a bacterial infection that involves hair follicles.

A cyst, on the other hand, is a fluid filled lump that occurs underneath the skin. A cyst is usually harmless, but if it becomes infected, it can develop into a boil.

Learn more about the differences between a boil and a cyst.

Frequently asked questions

Here are some more frequently asked questions about boils.

How do I get rid of a boil fast?

Although a boil may go away on its own without requiring medical treatment, you can encourage healing with home remedies. You can treat a boil at home by applying a warm washcloth for around 10 minutes at a time four times per day.

Should I pop a boil?

It is important that you do not pop, squeeze, or scratch a boil. This can cause the infection to spread, which can result in serious complications, such as lymphangitis or lymphadenitis.

How long do boils take to go away?

It can take anywhere from 2 days to 3 weeks for the pus to naturally drain from a boil. If a boil does not go away after a few weeks, or if it does not respond to treatment, contact your doctor for advice.

Can boils make me sick?

A boil can make you feel unwell, particularly if you have multiple boils that develop into a carbuncle. This can make you feel weak and tired, and you may have a fever.

If you pop or scratch a boil, it can cause the infection to spread. This can cause serious complications, so it is important to avoid popping the boil.

Summary

Boils occur when bacteria on the surface of the skin enter the body. This causes a lump or bump that is filled with pus.

A boil can heal on its own within days or weeks. You can also encourage healing by keeping the area clean and applying a warm washcloth to the area around four times per day. If the boil does not respond to treatment, or if you develop a carbuncle, your doctor will be able to drain the pus in a sterile environment.

Contact your doctor if you have concerns about a boil. They will be able to carry out tests to identify the bacteria causing the boil and advise on the best treatments for you.

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Medical Reviewer: Madeline Knott, MD
Last Review Date: 2022 Jul 27
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