Medically Reviewed By William C. Lloyd III, MD, FACS
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What are pustules?

Pustules are small, pus-filled sores located at the surface of the skin. They are most commonly seen in acne, although they can be a sign of any infection involving the skin. Pustules appear on the skin as small, raised, reddened areas that typically have a whitish center. They may or may not be painful or tender to the touch. Pustules most commonly occur on the face, chest and shoulders and in areas of increased sweating.

Pus is caused by the breakdown of inflammatory cells produced by the body to fight infection. Typically, pus forms during the course of a bacterial infection. Although neutrophils (type of immune system cell) initially engulf and kill bacteria, they themselves are eventually broken down and become a major constituent of pus. All types of bacteria that cause disease are capable of producing infections that lead to pus.

In some cases, conditions other than bacterial infections can produce skin pimples or bumps that have the appearance of pustules. These include chickenpox, yeast infections, and herpesvirus infections such as cold sores or genital herpes.

The formation of pustules may be a symptom of a bacterial infection, which may be a serious condition. Seek prompt medical care if you have pustules that are persistent or recurrent or that cause you concern.

What other symptoms might occur with pustules?

Pustules can be caused by bacterial infections and may accompany other symptoms, which vary depending on the underlying disease, disorder or condition.

Other symptoms that may occur along with pustules

Pustules may be accompanied by symptoms localized to the skin or related to other body systems including:

Symptoms that might indicate a serious condition

In some cases, pustules may occur with other symptoms that might indicate a serious condition that should be immediately evaluated in an emergency setting. Seek immediate medical care (call 911) if you, or someone you are with, have pustule formation along with other serious symptoms including:

What causes pustules?

Pustules are caused by the accumulation of pus at the surface of the skin. Although pus formation typically indicates a bacterial infection, pustules are most commonly seen in acne, which is caused by the clogging of pores in the skin and the subsequent accumulation of oil and bacteria.

Common causes of pustules

Pustules may be caused by infections or other common conditions including:

  • Acne

  • Boils

  • Candidiasis (yeast infection)

  • Chickenpox

  • Cold sores

  • Folliculitis (inflammation and infection of hair follicles)

  • Hand-foot-and-mouth disease (mild, contagious viral disease, usually seen in children, that typically affects the skin of the hands and feet and membranes inside the mouth)

  • Impetigo (contagious bacterial skin rash that occurs most commonly in children)

  • Pustular psoriasis (chronic skin disease characterized by eruption of pustules and areas of scaly, itchy skin)

What are the potential complications of pustules?

Pustules are generally a harmless symptom that do not produce long-term complications. However, in some circumstances, pustule formation may accompany a serious bacterial infection that has the potential to spread to other organs via the bloodstream. Complications of such bacterial infections include:

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Jan 2
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
  1. Pustules. Medline Plus, a service of the National Library of Medicine National Institutes of Health. http://www.nlm.nih.gov/medlineplus/ency/article/003234.htm
  2. Skin abscess. Medline Plus, a service of the National Library of Medicine National Institutes of Health. http://www.nlm.nih.gov/medlineplus/ency/article/000863.htm
  3. Bacterial infections.Medline Plus, a service of the National Library of Medicine National Institutes of Health. http://www.nlm.nih.gov/medlineplus/bacterialinfections.html
  4. Stevens DL, Bisno AL, Chambers HF, et al. Practice guidelines for the diagnosis and management of skin and soft-tissue infections. Clin Infect Dis 2005; 41:1373.