Folliculitis, Furuncles, and Carbuncles Skin Infections

Skin infections are very common occurrences throughout life. Some infections are self-limiting and resolve on their own, but many others require medical attention. Bacterial skin infections technically have specific names based on their origin and extent, but in the medical community they are often lumped into one of two categories: "boil" or "abscess." This article will clarify the technical terms that are used to describe the diagnosis of infections that are caused by the bacterium Staphylococcus aureus (also known as "staph" for short).


Folliculitis is an infection that is localized to the hair follicle. Folliculitis looks like small, yellow pustules that are confined to the hair follicle. Factors that can lead to the development of folliculitis include:

  • Trauma
  • Chronic friction
  • Occlusive clothing
  • Occlusive chemicals
  • Excessive sweating
  • Exposure to water

This photo contains content that some people may find graphic or disturbing.

Boil on skin
DermNet / CC BY-NC-ND

Hot Tub Folliculitis

A special case of folliculitis that is not caused by the bacterium S. aureus is hot tub folliculitis. This self-limited infection is caused by a different bacterium called Pseudomonas aeruginosin that tends to be itchy and can be contracted from hot tubs, whirlpools, and pools that have inadequate chlorine levels.

This photo contains content that some people may find graphic or disturbing.

Spa pool folliculitis
 DermNet / CC BY-NC-ND


A furuncle is an infection of the pilosebaceous unit, and, therefore, is more extensive than folliculitis because the infection also involves the sebaceous gland. A furuncle frequently occurs on the neck, face, armpits, and buttocks.  It begins as a small, tender, red nodule that becomes painful and fluctuant (in other words, you can compress it when you touch it). Frequently, pus will spontaneously drain, and often the furuncle will resolve on its own. Factors that contribute to the development of furuncles include:

  • Obesity
  • Blood disorders
  • Taking oral steroid medications
  • Diabetes


A carbuncle can simply be defined as multiple furuncles that are grouped together. A carbuncle usually involves the deeper layers of the skin: the subcutaneous fat. It looks like a large, red nodule, feels hot, and may have visible layers of pus just beneath the surface of the skin.

This photo contains content that some people may find graphic or disturbing.

Carbuncle on skin
 DermNet / CC BY-NC-ND


Mild cases of folliculitis and small furuncles may heal on their own with good hygiene and wound care. More extensive furuncles and all carbuncles need to be treated with antibiotics such as dicloxacillin or cephalexin. If pus or in duration (a hard mass) are present, in addition to antibiotics, a procedure called incision and drainage (I&D) should be performed to drain the pus and allow the lesion to heal from the inside out.

When You Think That You Might Have a Skin Infection

If you are concerned that you may have a skin infection, such as folliculitis, hot tub folliculitis, a carbuncle, or a furuncle, ask your general practitioner for a referral to a dermatologist, a doctor who specializes in treating the skin, hair, and nails. A dermatologist can evaluate whatever is bothering you, make a diagnosis, and come up with an appropriate treatment plan. Sometimes skin infections are minor, but other times they can be life-threatening, so it's always a smart idea to see a doctor right away to be safe. 

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Winters RD, Mitchell M. Folliculitis. In: StatPearls [Internet]. Updated 18 Sep 2019.

  2. Guida M, Di Onofrio V, Gallè F, et al. Pseudomonas aeruginosa in Swimming Pool Water: Evidences and Perspectives for a New Control StrategyInt J Environ Res Public Health. 2016;13(9):919. doi:10.3390/ijerph13090919

  3. Ibler KS, Kromann CB. Recurrent furunculosis - challenges and management: a reviewClin Cosmet Investig Dermatol. 2014;7:59–64. doi:10.2147/CCID.S35302

  4. Institute for Quality and Efficiency in Health Care (IQWiG). Boils and carbuncles: Overview. [Internet]. Updated 14 Jun 2018.

  5. Ki V, Rotstein C. Bacterial skin and soft tissue infections in adults: A review of their epidemiology, pathogenesis, diagnosis, treatment and site of careCan J Infect Dis Med Microbiol. 2008;19(2):173–184. doi:10.1155/2008/846453

By Heather L. Brannon, MD
Heather L. Brannon, MD, is a family practice physician in Mauldin, South Carolina. She has been in practice for over 20 years.