Slideshow: A Visual Guide to Boils

Nemours Foundation: “Staph Infections.”

Causes of Skin Boils with Pictures

Rod Brouhard is an emergency medical technician paramedic (EMT-P), journalist, educator, and advocate for emergency medical service providers and patients.

Updated on October 22, 2022

Michael Menna, DO, is a board-certified, active attending emergency medicine physician at White Plains Hospital in White Plains, New York.

Skin boils are infections caused by bacteria or fungi. They commonly develop as a lump around a hair follicle or oil gland. Looking at pictures of boils and understanding the conditions that cause them can help you recognize them if they appear on your body. This can help guide you in seeking treatment.

This article explains boil symptoms, how boils differ from similar skin conditions, and conditions that result in boils.

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Boil Symptoms

Skin boils are often caused by an infection with Staphylococcus bacteria. They may also develop from other infectious agents, like group A Streptococcus.

Skin boils can have a pinkish, red, or whitish-yellow color with symptoms that include:

• Swelling
• Oozing of pus or clear fluid
• Pain

Boil vs. Pimple

Skin boils and pimples can look similar, but there are differences. For example, unlike boils, pimples aren’t caused by an infection. Instead, they are caused by blocked pores. This blockage causes pimples, blackheads, and whiteheads to form a bump on the skin. Pimples are the main symptom of acne, a common skin condition.

Sometimes, with acne, bacteria can infect clogged pores, leading to redness and inflammation. This type of acne is known as inflammatory acne.

Boil vs. Cyst

Boils also differ from cysts, which are fluid-filled sacs that are typically non-infectious and non-contagious. However, cysts can become infected if bacteria get in broken skin. In addition, boils usually multiply and can be painful, while cysts typically grow slowly and aren’t painful.

Many people also misidentify a boil for a bug or spider bite. Unless you catch a spider in the act of biting, an infection likely is what’s causing a boil.

MRSA Blister

A blister caused by methicillin-resistant Staphylococcus aureus (MRSA) infection is also called a staph infection. But even though it’s common for MRSA to show up as blisters or boils, not all blisters or boils are from MRSA.

Other forms of MRSA and group A Streptococcus bacteria cause skin infections that look very similar.

Symptoms

MRSA can colonize (live) on the skin and cause no harm. However, when you have a cut or scrape, the bacterium can enter the body and cause infection. When this occurs, symptoms may include:

MRSA can spread by touching someone’s skin colonized with MRSA or touching contaminated surfaces.

MRSA blisters commonly form on areas covered by hair, such as the back of the neck, groin, buttocks, armpit, and beard areas.

Treatment

Due to this bacterium’s resistance to many standard antibiotics, treating it requires specific types of medication and dosages. Usually, treatment involves a seven to 10-day course of oral antibiotics such as:

• Trimethoprim-sulfamethoxazole
• Clindamycin
• Minocycline
• Linezolid
• Doxycycline

Cutting an MRSA boil open to drain it should only be done by a healthcare professional using a sterile technique to avoid spreading the MRSA or introducing another infection.

Cystic Acne

Cystic acne is the most severe type of acne. It causes acne cysts that form deep under the skin.

It occurs when pores become clogged with excess sebum (an oily substance found in glands) and dead skin cells. When bacteria infect these clogged pores, the immune system reacts to fight the threat. This reaction causes deep swelling in the skin’s middle layer (the dermis).

Symptoms

An acne cyst is usually red and may have a whitish-yellow head. A cyst can be crusty, painful, or tender to touch, and either large or small in size.

Since the face has an abundance of oil glands, acne cysts tend to appear there. However, they can also appear on the back, butt, chest, neck, shoulders, and upper arms.

Treatment

Treating cystic acne typically includes taking oral antibiotics and applying certain topical gels or creams (often prescription-strength) to the affected area. Some treatments include the use of:

• Azelaic acid
• Benzoyl peroxide
• Retinoids
• Salicylic acid
• Accutane (isotretinoin)

Impetigo

Impetigo is a bacterial skin infection that is pretty common in kids (in fact, some incorrectly pronounce it infantigo). It comes from either Staphylococcus or Streptococcus bacteria.

Impetigo is highly contagious and spreads through contact with an infected person’s sores or the fluid from these sores. It can also spread by sharing towels or clothing with an infected person.

Symptoms

Symptoms of impetigo typically occur within three days after infection. They can include:

• Skin lesions on the lips, nose, arms, and legs
• Pus-filled blisters that easily burst
• Reddish skin with blisters that contain tan or yellowish fluid
• Rash

Treatment

Impetigo is treatable and doesn’t cause a fever. Healthcare providers will most likely be able to identify it just by looking at it. However, if they aren’t sure, they may take a biopsy of the affected skin.

Treating impetigo typically involves applying prescribed topical antibiotics such as mupirocin. Oral antibiotics such as cephalosporins, clindamycin, and sulfamethoxazole may also be used.

Hidradenitis Suppurativa

Hidradenitis suppurativa , sometimes referred to as acne inversa, is a chronic skin disease that affects the sweat glands and hair follicles. This condition causes bumps on the skin that can turn into painful boils. After they heal, scarring occurs.

The reason some people develop this condition is unknown. However, it’s thought that sex hormones and lifestyle factors like smoking may play roles.

Experts believe that hidradenitis suppurativa occurs when an abnormal growth of cells clogs hair follicles. This debris buildup eventually causes the follicle to rupture, leading to inflammation and scarring. Inflammation is an immune system response to aid in the healing process.

Symptoms

Symptoms of hidradenitis suppurativa include:

• Pain
• Swelling
• Pimple-like, pus-filled lesions
• Scarring

The condition typically affects areas where skin touches skin, such as the underarms, groin, buttocks, and breasts.

Treatment

For mild cases, treatment usually involves taking anti-inflammatory medications. In addition, applying topical cleansing agents, such as acne washes and antibacterial soaps, can help.

Treatment for more severe cases may include:

• Corticosteroids
• Antibiotics such as tetracycline and erythromycin
• Humira (adalimumab)
• Acne surgical procedures

Stye

A stye ( hordeolum ) is a painful, red bump that develops on the eyelid. It’s usually caused by a blockage of oil-producing glands in the eyelash follicle and Staphylococcus bacterial infection.

A stye can form either on the outer or inner eyelid. A stye isn’t usually contagious, but it can release small amounts of bacteria. This bacteria can spread through physical touch or contact with items such as pillows.

Symptoms

Symptoms of a stye can include:

• Eyelid crusting
• Teary or scratchy eyes
• A painful swelling on the eyelid
• Light sensitivity

Treatment

Styes typically clear without medical treatment in one to two weeks. Self-care methods may speed healing. A common way to clear a stye is to place warm compresses on the eyelid for 10 to 15 minutes at a time, three to five times a day.

Seeing an ophthalmologist may be wise if your stye doesn’t improve with at-home care. They may prescribe topical or oral antibiotics and ensure there’s no underlying problem. Also, a healthcare provider may surgically drain a stye if it blocks vision or does not clear with antibiotics.

Carbuncle

A single boil is called a furuncle. A carbuncle is a cluster of boils that form on a particular body area. Like a boil, a carbuncle results from a bacterial infection, usually by Staphylococcus aureus.

Research reveals that carbuncles are commonly associated with diabetes.

Symptoms

Because a carbuncle affects deeper layers under the skin, symptoms are more severe than a single boil.

Typically, the affected area is red and inflamed with multiple pus-filled boils. Carbuncles can develop anywhere on the body, but they commonly occur on the back and neck. A carbuncle may also include symptoms like:

Treatment

Although warm compresses may help it drain, it’s not uncommon for a carbuncle to need to be surgically drained by a healthcare provider. A healthcare provider may also prescribe antibiotics like trimethoprim-sulfamethoxazole and doxycycline, especially if it returns.

When to See a Doctor

Skin boils usually heal on their own, especially with proper self-boil treatment. However, some things may indicate an infection is brewing. If you notice any of the following, contact a healthcare provider:

• Fever
• Boils that last longer than one week
• Multiple boils or carbuncles
• Boils that return

A healthcare provider can give proper treatment and ensure there isn’t an underlying problem.

See a healthcare provider if you develop a boil and have diabetes or a condition that affects the immune system.

Summary

Many things may cause boils, including MRSA, cystic acne, impetigo, hidradenitis suppurativa, styes, and carbuncles. Symptoms vary depending on the condition but usually include sensitive pus-filled lesions.

Treatment varies depending on the cause. If you have any signs of infection or the boil isn’t responding to at-home treatment, you should contact a healthcare provider.

Frequently Asked Questions

What is the best antibiotic for skin boils?

There isn’t a clear-cut best antibiotic for skin boils. Some antibiotics may work better than others in clearing a particular bacterium that causes a skin boil. For example, trimethoprim-sulfamethoxazole, clindamycin, and minocycline are more successful in treating an MRSA infection. But skin boils caused by non-MRSA conditions can usually be treated with antibiotics like amoxicillin, cephalosporins, and dicloxacillin.

How do you prevent boils?

Practicing proper hygiene can help prevent boils. For example, washing your hands frequently and bathing regularly can help prevent the spread of bacteria. Also, try avoiding physical contact and sharing items like washcloths and towels with those who have a staph infection or boil, as the bacteria can spread through contact.

How long do boils last?

Without treatment, a boil may take up to two weeks or more to heal. However, with treatment, boils may clear much faster.

Slideshow: A Visual Guide to Boils

A boil is a common, painful infection of a hair follicle and the surrounding skin. It begins as a red lump, then fills with pus as white blood cells rush in to fight the infection. Good home care can often clear up a single boil, also known as a skin abscess. A doctor’s care is needed when a boil resists treatment or develops in certain vulnerable areas of the body.

Boil Symptoms

2/19

Boils are usually pea-sized, but can grow as large as a golf ball. Symptoms can include:

• Swelling, redness, and pain
• A white or yellow center or tip
• Weeping, oozing, or crusting

You may also have a general feeling of ill health, fatigue, or a fever, which is reason to call a doctor.

Where Do Boils Form?

3/19

Boils can form anywhere on the body, but they’re most common on the face, neck, armpits, shoulders, back, and buttocks. Hairy, sweaty areas are typical sites, as well as areas of friction, such as the inner thighs. Boils can also develop around the ear or near the nose. The pain often worsens as pus collects under the skin, then eases as fluids begin to drain.

What Causes Boils?

4/19

Most boils are caused by staph bacteria (Staphylococcus aureus), which many healthy people carry on their skin or in their noses without a problem. When a scrape, cut, or splinter breaks the skin, the bacteria can enter a hair follicle and start an infection. Others boils, such as those associated with acne, develop from clogged pores that become infected.

Ordinary Boil or MRSA Infection?

5/19

MRSA can look exactly like an ordinary boil: red, swollen, pus-filled, and tender. But MRSA infections are caused by one particular type of staph that is resistant to many antibiotics. If a skin infection spreads or doesn’t improve after 2-3 days of antibiotics, your doctor may suspect MRSA. The right treatment given promptly is important to heal a MRSA infection and prevent a deeper, more dangerous infection.

Are Boils Contagious?

6/19

Not exactly, but the germs that cause boils (staph) are easily spread through skin-to-skin contact and contaminated objects. These bacteria usually do no harm unless they find a break in the skin. To avoid spreading staph, don’t share towels, bedding, clothes, or sports gear while you have a boil. Avoid touching the boil, and keep it covered. Frequent hand washing can also help prevent spreading the bacteria.

Early Warning: Folliculitis

7/19

Folliculitis is an inflammation or infection of the hair follicles that can develop into a boil. Tiny pimples with whiteheads appear around individual hairs, sometimes surrounded by red skin. It can be itchy, tender, and uncomfortable, but is typically not as painful or deep as a boil. Shaving or friction from tight clothing can let staph bacteria slip under the skin — the most common cause of both folliculitis and boils.

Boil Type: Carbuncle

8/19

When several boils form close together and join beneath the skin, it’s called a carbuncle. They are most commonly found on the back and the neck but can develop anywhere. Men are more likely to develop carbuncles than women. A carbuncle tends to lie deeper beneath the skin than a boil and can take longer to heal.

Boil Type: Cystic Acne

9/19

Cystic acne is a type of skin abscess that forms when oil and dead skin cells clog a hair follicle, creating a place where bacteria grow and thrive. It affects deeper skin tissue than regular acne, leading to firm, painful cysts. It’s most commonly on the face and shoulders and typically occurs in the teenage years.

Boil Type: Armpit and Groin

10/19

When lumps and pus-filled abscesses repeatedly develop in these areas of the body, it may be a chronic condition called hidradenitis suppurativa. Infection starts in sweat glands and hair follicles that become blocked. Mild cases heal with home care. Several drugs and treatments are available for more serious and recurring cases.

Boil Type: Pilonidal Abscess

11/19

When a boil forms in the skin just above the buttocks crease, it may be a pilonidal abscess. Hair is believed to play a role, and irritation, pressure, and prolonged sitting may also contribute to the development of a cyst here. If a cyst becomes inflamed and infected, it becomes an abscess. Some children are born with a “pilonidal dimple” where infections can crop up. Signs of infection require a doctor’s attention.

Boil Type: Stye

12/19

The familiar “stye on the eye” is a boil, usually caused by staph bacteria. It starts in the follicle of an eyelash and may be red, warm, swollen, and uncomfortable. A stye is sometimes confused with a chalazion, which is also a lump on the eyelid, but a chalazion is usually painless and is caused by a blocked oil gland, not an infection.

Who Gets Boils?

13/19

Anyone can develop a boil. The risk increases with:

• Close contact with an infected person
• Acne, eczema, or other causes of breaks in the skin
• Diabetes
• A weakened immune system

Treatment: Home Care

14/19

You can take care of most boils at home. Apply warm, moist compresses several times a day to help a boil open and drain. After it starts draining, keep it clean, and continue using warm compresses — a clean one every time. Change the bandage often and wash hands well. Resist the urge to squeeze or pop the boil. This can make the infection worse.

When to Call the Doctor

15/19

If a boil doesn’t heal after a week of home care, call your doctor. Other reasons to call include:

• A boil on the face or spine
• A fever or red streaks coming from the sore
• A very large or painful boil
• A boil that keeps coming back

Treatment: Procedures

16/19

If the fluid inside a boil doesn’t drain by itself, your doctor may prick the top of the sore with a sterile instrument to be sure it drains completely. A deep infection may be packed with sterile gauze so it continues to drain. Antibiotics and steroid shots are sometimes given to help with healing.

Treatment: Recurrent Boils

17/19

For some people, boils are a recurring problem. In addition to standard treatment, your doctor may try to eliminate or reduce staph bacteria throughout the body. This can include any or all of the following treatments: washing up with a special antiseptic soap, using an antibiotic ointment inside the nose, or, if necessary, 1-2 months of antibiotics taken by mouth.

Boil Complications

18/19

Most boils heal with home treatment or a doctor’s visit. Sores on the face may require antibiotics because they’re so close to the eyes and brain. Rarely, the staph bacteria from a boil or carbuncle can get into the bloodstream, which can then affect the heart and other internal organs.

How to Prevent Boils

19/19

Since bacteria are everywhere in our environments and on many people’s skin, the best defense against boils includes:

• Hand washing or use of alcohol-based hand sanitizer
• Careful cleaning of cuts, scrapes, and other wounds
• Keeping wounds covered
• Not sharing towels, sheets, razors, etc.

Wash towels, sheets, and anything else in contact with an infected area in very hot water. Throw away any wound dressings in a tightly sealed bag.

Show Sources

IMAGES PROVIDED BY:

1) Peggy Firth and Susan Gilbert for WebMD
2) Dr. P. Marazzi / Photo Researchers, Inc, Watney Collection / Phototake, ISM / Phototake
3) Watney Collection / Phototake, ISM / Phototake, Biophoto Associates / Photo Researchers, Inc, Interactive Medical Media LLC
4) David Mack / Photo Researchers, Inc
5) Interactive Medical Media LLC
6) Stockbyte
7) Interactive Medical Media LLC
8) Peggy Firth and Susan Gilbert for WebMD
9) Anna Webb/WebMD
10) Interactive Medical Media LLC
11) Peggy Firth and Susan Gilbert for WebMD
12) Phototake
13) Medioimages/Photodisc
14) Fuse
15) Dr. Harout Tanielian / Photo Researchers, Inc.
16) Siri Stafford/Photodisc
17) Stockbyte, iStock
18) Medioimages/Photodisc
19) Sean Justice/Digital Vision

Nemours Foundation: “Staph Infections.”

University of Chicago Medical Center: “MRSA FAQ.”

Merck Manual of Medical Information, 2nd Home Edition: “Folliculitis and Skin Abscesses.”

NIH Genetics Home Reference: “Hidradenitis Suppurativa.”

Hidradenitis Suppurativa Foundation: “What is Hidradenitis Suppurativa?”

American Academy of Ophthalmology: “What Are Chalazia and Styes?”