Approved Doctor(s) ; Shamali Hoque , Christian L. Baum • Feb 09, 2024

Table of contents

What is a boils?

It is defined as a painful and pus-filled swelling under the skin caused by bacteria infecting and inflaming one or more hair follicles. Boils, which usually start as red or purple tender bumps, soon fill with pus and begin to swell. The boil grows over time and continues to swell and hurt until it ruptures. The areas most likely to be affected by boils include the neck, face, armpits, thighs and buttocks.

When boils form a connected area of infection under the skin, it is called carbuncle. Carbuncles can also be called boil clusters.

Symptoms of boils

While boils can appear on any part of the body, they are usually seen in areas where friction and sweating are most common. The symptoms of boils include the following.

  • Painful red swelling that starts small but can grow to more than 5 centimeters
  • Reddish or purplish swollen skin around the lump
  • Increased swelling seen within a few days
  • Development of a yellow-white tip caused by rupture and outflow of pus

If people develop carbuncles, the infection is more serious and deeper. For this reason, scarring is more likely to remain after healing. In addition, the symptoms that can be seen in patients with carbuncles include the following.

  • Patients do not feel well
  • Fire
  • Tremor

Causes of boils

Boils are caused by Staphylococcus aureus bacteria that are commonly found on the skin. These bacteria can enter the lower part of the skin through minor injuries to the skin or through factors such as insect bites.

Risk factors for boils

No matter how healthy a person is, there is always the possibility of boils. However, some risk factors increase the likelihood of boils. These risk factors include the following.

  • Living with someone who has boils
  • Having diabetes
  • Damage to the skin's protective barrier for any reason
  • Weakening of the immune system

Complications of boils

Boils rarely cause complications. The most common complication is getting the infection into the bloodstream. In this case, sepsis is common. However, infection in the bloodstream can lead to infection deep in the body, such as endocarditis and osteomyelitis.

Which diseases can boils be a sign of?

Boils are a health problem that can also be seen in healthy people. However, recurring boils can be a symptom of other health problems. These health problems include the following.

  • Weak immune system
  • Diabetes
  • Incomplete skin cleansing
  • Friction and injuries
  • Family history

Eye boils

The eye boil, which manifests itself as a painful pimple-like swelling on the eyelid, is seen due to infection in the sebaceous glands in the eyelid or in the eyelash roots. It is usually seen due to inadequate eye hygiene and the use of dirty contact lenses. Other factors affecting the occurrence of eye boils include the following.

  • Weak immune system
  • Chronic diseases
  • Minor injuries
  • Allergic diseases
  • Secretion accumulated in the sebaceous glands
  • Blockage of hair follicles

Boil popping

Boils should not be burst for treatment purposes. Puncturing or bursting boils causes the infection-causing bacteria to spread. This can lead to an increase in infection or to the infection entering the circulatory system, leading to more serious clinical manifestations.

Boil treatment

Small boils can be treated at home. Applying a warm compress will be sufficient to relieve the pain caused by the boil and provide natural drainage. However, treatment options for large boils or carbuncles include the following.

Incision and drainage

An incision can be made to drain a large boil or carbuncle. In deep infections that do not drain completely, sterile gauze can be placed on the incision site to absorb and remove the pus.


In severe or recurrent infections, antibiotics may be prescribed to help recovery.

Types of boils

There are different types of boils. However, the most common types of boils include the following.

Oriental furuncle

Oriental furuncle, also called Aleppo boil, is caused by the transmission of a parasite called cutaneous leishmaniasis by sand flies. It starts with pimple-like blisters, especially on the hands, face and feet. As the infection progresses, they turn into 1- to 2-centimeter-sized sores and leave permanent scars if left untreated.

Black boils

The black boil, also called shepherd's boil, is known as anthrax. It is caused by Bacillus Anthracis, a bacterium found in animals such as sheep, cows and goats. Black boils, which start with water-filled blisters, cause itching. Over time, the central part of the swelling darkens and becomes painless.

Shirpençe boils

This type of boil, also called lion's claw, is called carbuncle in medicine. It causes more severe symptoms than other types of boils.

How to prevent boils?

It is not always possible to prevent boils, especially in people with weakened immune systems. However, taking the following precautions will help to avoid boils.

  • Regular hand washing with soap
  • Use of alcohol-based hand sanitizers
  • Keeping cuts and abrasions clean and covered
  • Not sharing personal belongings
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