Causes, Symptoms, and Treatment of Skin Boils

Skin boils look like really big pimples and can be mistaken for spider bites. Boils (also called furuncles or carbuncles) are caused by staph bacteria and appear as a red to purple lump on the skin with a white head that contains a white-yellow pus.

Many people think of a boil as a large pimple that is "boiling over." This certainly can help you identify one. This type of skin lesion is relatively common and can clear up within two weeks with proper care. Treatment is typically done at home, though you may need to see your doctor if the boils are particularly bad or get worse.

Causes of Skin Boils

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Skin boil
Skin boil.

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Skin boils are caused by infections from what is commonly known as "staph" bacteria. The most common bacteria are Staphylococcus aureus or group A Streptococcus. Both of these are treated with antibiotics. Methicillin-resistant Staphylococcus aureus (MRSA) is more difficult to treat but looks similar to other forms of staph. Boils can also be caused by fungi.

The infection affects the natural openings that surround hair follicles and typically infects a group of follicles at a time. This causes the red lump, pain, and itching.

When the follicles are damaged, the bacteria can grow into the surrounding skin tissue. Though it's rare, the infection can get into the bloodstream and cause serious illness. For this reason, it's important to learn how to treat boils and when to seek medical attention.

Symptoms of Skin Boils

Boils hurt and itch. A boil is usually diagnosed by its appearance. The symptoms can be summed up as a red, swollen bump surrounded by red, irritated skin. Eventually, there will be one or more small whiteheads (pustules) in the center that are filled with a white or yellow pus-like fluid. Once in a while, boils heal without forming a white head.

A boil (furuncle) that develops multiple heads is called a carbuncle.

Boils come in all sizes. They may begin pea-sized and can grow to about that of a golf ball and this can happen rather quickly.

Boils can occur anywhere on the body. They are most common on the face, neck, armpit, buttocks, and thighs. It is possible for boils to occur only once, though some people experience them chronically. 

Your skin may itch before a boil actually appears. You may feel fatigued or generally ill once the boil forms. See your doctor if you develop a fever or chills.

Risk Factors

Boils occur most often in teenagers, young adults, and communal living situations. Antibacterial soaps and good hygiene can do a lot to prevent the spread of the infection.

Athletes who play contact sports or share equipment can spread the staph bacteria. It's also an issue in military barracks, homeless shelters, and other places where people live in close quarters.

Other people who are at high risk are those with illnesses like diabetes and skin conditions like eczema. Staph infections can cause chronic outbreaks of boils.

In addition, anyone who does not get proper nutrition, is obese, or has a weak immune system has a better chance of developing boils. In these cases, the body has a harder time fighting off the bacteria.


Treating a skin boil depends on the cause. In some cases, treatment will require the intervention of a healthcare provider. However, there are some first aid tips you can try at home to make boils more tolerable and encourage them to heal on their own.

First, keep the boil clean and cover it with a clean, dry dressing. Wash your hands after touching the boil or changing the dressing. Placing a warm, moist cloth on the boil might help the boil come to a head, break, drain, and heal.

Do not pop the boil or lance it yourself. You want it to break and drain naturally. Never re-use a cloth used on a boil unless it has been laundered in hot water. Don't share items that have been in contact with the boil, and be sure to launder them in hot water.

When to See the Doctor

See your doctor if your boil has these characteristics:

  • A boil on your spine or on your face, due to the risks of an infection in those locations
  • A boil that doesn't heal within two weeks
  • Fever or chills
  • A boil that is painful or in an uncomfortable location
  • A red streak that develops from the boil

The doctor can drain a larger boil. While it's not typical, antibiotics can be used to reduce the infection. A doctor may also be able to help with the pain.

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Article Sources
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  1. Ibler KS, Kromann CB. Recurrent furunculosis - challenges and management: a review. Clin Cosmet Investig Dermatol. 2014;7:59-64. doi:10.2147/CCID.S35302

  2. Cleveland Clinic. Boils & carbuncles. Reviewed April 15, 2016