Boils and Carbuncles: Types, Symptoms, Causes, Risks, Complications, Diagnosis, Treatment, Prevention and Prognosis

Boils and Carbuncles


Boils are small reddish swollen lesions on the skin that is filled with pus. Bacteria are the most common cause of boils such as the Staphylococcus aureus. The bacterium usually goes into the hair follicles of the skin that are prone to sweat, occlusion, and friction.
Boils are commonly seen on the neck, armpits, thighs, shoulders, and buttocks.

2Types of Boils

Pilonidal Cysts

Pilonidal cysts are boils that appear between the buttocks. This kind of boil usually require medical treatment like drainage and packing (putting gauze in the infected area to allow continuous draining).

Hidradenitis Suppurativa

Hidradenitis Suppurativa or the “acne inverse,” is a chronic skin infection characterized by boil-like lumps or sebaceous lumps which can be found in the armpits, under the breasts, inner thighs, groins and some parts where sweat glands are near.  If sweat glands are blocked, skin infections may start to appear.

Cystic Acne

Cystic Acne is formed when an excessive secretion of sebaceous oils, this can clog the hair follicles and can cause local inflammation on the skin. This is most common in teenagers.


Folliculitis is an infection of the hair follicles. It may develop in areas with hair most commonly seen in the beard area, arm, legs, and buttocks. Shaving or wearing tight clothes causes friction and can irritate the follicles leading to folliculitis.


A carbuncle, on the other hand, is a cluster of boils. Usually, a carbuncle is bigger than a boil and has one or more openings that drain pus onto the skin. They can form in the same area as boils and may also be found on the face, scalp and the buttocks. Anyone can have boils and carbuncles, but mostly it occurs in children, teenagers, and young adults.


Boil (furuncle)

Is a localized skin infection that starts as tender, red and painful lump rapidly fills with pus which may spontaneously drain, weep and ooze. This can happen until two to three weeks (2-3 weeks).


Have more than one head, or more openings are more serious skin infection than boils.
In addition to the same symptoms as seen in boils, carbuncles may cause fever and chills and sometimes body malaise (a general feeling of being ill or without energy). It may also heal slowly, and it may scar the skin.


Boils and carbuncles are usually caused by bacteria specifically Staphylococcus aureus. Some Staphylococcus develops into abscesses and can become seriously infected.
Other types bacteria or fungi found on the epidermis can also cause furuncles (boils) and carbuncles.

Most of the time once the pores or sweat gland becomes clogged, it can cause infection. Microbes or bacteria gets trapped inside the pore causing the area to become red and inflamed or swollen.

5Risk factors


People having diabetes are more likely to get boils due to high levels of blood sugar (Hyperglycemia) that weaken the immune system defenses thus increasing the body’s vulnerability to infection.


Eczema also is known as atopic dermatitis can also be another risk factor. This is a chronic inflammatory skin condition that causes the skin to become inflamed and irritated.

People with Chronic Diseases

Other individuals having chronic diseases or conditions like cancer or those taking medications such as immune suppressing drugs (corticosteroids/ chemotherapy) that reduce the skin’s ability to fight germs, are more likely to develop furuncles and carbuncles and other skin infections.

Skin Infection

Boils may also result from an infection of a scrape or cut in the skin. Germs may enter through this cut and can travel from the hair to the follicles

Poor Hygiene

People who have poor hygiene, using cosmetics that clog the pores and those exposed to harsh chemicals that can irritate the skin, are also susceptible to develop furuncles and carbuncles.


Individuals who are overweight or obese are most likely to develop boils and carbuncles.


Boils are very contagious and can become serious.It can spread to other people and on rare occasions can cause infection of the bloodstream and other parts of the body.
An individual with a low or compromised immune system might develop other serious infection or might trigger another secondary infection. Such possible complications are the following:


This is a serious complication of an infection. If left untreated, it could be life threatening.


This is an infection of the blood/ bloodstream


This is an infection of the inner layer of the heart

Brain abscess:

This is a collection of pus developing inside the brain. Boils around the nose or eyes can spread in the brain and can become a serious infection.

Permanent Scarring:

This occurs following a larger boil or furuncle that has been incised or drained. Though it never disappears completely, it will fade in time.


This is an infection developing inside the bone.

MRSA (methicillin-resistant Staphylococcus aureus) infection:

This is caused by staphylococcus bacteria that is tougher to treat since it becomes resistant to any widely used antibiotics.


Usually, a physical exam is needed. The health care provider will assess the boil or carbuncle basing on how it looks. For individuals with recurrent infection, a sample of the pus is taken and sent to the laboratory to undergo culture and sensitivity test to look for bacteria (staphylococcus) or other bacteria.

Laboratory testing can help determine what type antibiotic treatment would work best especially in situations where there is resistance to certain types of bacteria.


Ideally, for simple boils, home treatment is necessary. As soon as you notice a boil, begin treatment at once to prevent later complications. Never attempt to squeeze or prick a boil or carbuncle just to release the pus because it can spread the infection to other parts of the body. It is best to apply warm compress with a damp wash cloth to the area for 10 to 15 minutes several times a day to speed healing and relieve some pain and pressure caused by the boil.

Observe the boil, once it’s soft and forms a white head (a pustule), it is ready to be drained. The skin heals quickly once the infected fluid (pus) comes out. An individual can experience pain relief once pus comes out.

A boil will break and drain naturally on its own if left alone. In some cases like larger boils and carbuncles, incision and drainage (cut into the skin to drain pus built up in the skin) may be required. Pilonidal cysts and sometimes hidradenitis suppurativa may require surgery wherein they remove the outer shell of the cyst to clear the boil.

Oral Antibiotics can be prescribed by doctors if boils and carbuncles cause fever and pain.  Usually, antibiotics are given for seven (7) days. This also helps eliminate bacterial infections and can heal severe or recurrent skin infections.  Antibiotics that are topical and oral can be used for the treatment of Cystic acne and hidradenitis suppurativa.

Most common drugs used to treat boils are the following:

Clindamycin (Cleocin): topically administered

Mupirocin (Bactroban): is a topical antibiotic that can be used to prevent further skin infection

Cephalexin (Keflex): is an antibiotic that can kill gram positive bacteria like staphylococcus aureus by destroying their cell wall which inhibits the bacteria to grow.

Flucloxacillin is the drug of choice against Staphylococcus aureus. Clarithromycin or erythromycin is given if penicillin is contraindicated to the patient.

Clients with decreased immune system are advised to seek a consultation with proper management. Also get treatment from a doctor if you have observed to have serious symptoms with the boil and if the boil persists or comes back. It is also best to consult a physician if the boils or carbuncles lasts longer than 2weeks and are located in your spine or the middle of the face and.

It is important to keep boils or carbuncles clean. Wash your hands before and after cleaning the boil. Change the dressing on the boils often. Throw out used dressings in a sealed bag to avoid cross contamination.


  • Good hygiene and the use of antibacterial soaps help prevent the buildup of bacteria on the skin thus reducing the hair follicles to become infected thereby preventing the formation of boils.
  • Despite the best hygiene and proper skin regimen, the likelihood of developing boils and carbuncle can still happen. To prevent this from happening, have your towels or washcloths. Never share or let others use your towels. Change your clothes and bed linens every day.
  • Items used that come in contact with the affected area should be laundered and soaked in very hot (above 55 °C ) soapy water before using them again.
  • Proper Hand hygiene (hand washing) should frequently be observed when you come in contact with the affected area. Also, avoid close and direct contact with persons having staphylococcus infection like boils or carbuncle.
  • Lifestyle changes are a must, get plenty of exercise and sleep. Eat foods that are rich in vitamins and minerals to boost your immune system and avoid stress; this can cause your body to release more hormones that can become a contributing factor in acne formation.


Boils (furuncles) and carbuncles can heal on their own and have an excellent prognosis. Others may respond well to medical treatment.