What causes sores?

Sores have many causes. The type and severity of sore varies with the underlying cause.

Common causes of sores include the herpes simplex virus (resulting in a cold or genital sore), allergic reactions, eczema, and chickenpox. Extended bed rest or use of a wheelchair may cause pressure sores. Sores may also occur as a symptom of an underlying disease or serious condition, such as diabetes, leukemia, or skin cancer.

Diseases and disorders known to cause sores

Common diseases and disorders known to cause sores include:

  • Autoimmune disorders
  • Bleeding disorders such as hemophilia (rare hereditary disorder in which the blood does not clot normally)
  • Cancers
  • Dermatitis (rash)
  • Diabetes (chronic disease that affects your body’s ability to use sugar for energy)
  • Eczema
  • Peripheral artery disease (PAD, also called peripheral vascular disease, or PVD, which is a narrowing or blockage of arteries due to a buildup of fat and cholesterol on the artery walls, which limits blood flow to the extremities)
  • Peripheral neuropathy (disorder that causes dysfunction of nerves that lie outside your brain and spinal cord)

Infections that may cause sores

Sores can result from a number of infections including:

  • Cellulitis (infection of the skin and underlying soft tissue)
  • Chickenpox
  • Herpes simplex virus
  • Influenza (flu)
  • Papillomavirus infection (plantar warts)
  • Paronychia (infection of the cuticle)
  • Scabies
  • Sexually transmitted infections such as syphilis
  • Shingles (herpes zoster)

Conditions and situations that may cause sores

Common conditions and situations that may cause sores include:

  • Bite and sting injuries
  • Drug allergies to medications such as penicillin or codeine
  • Extended bed rest
  • Food allergies (allergic reaction to certain foods)
  • Medication side effects or reactions
  • Stress or irritation
  • Trauma
  • Weakened immune system
  • Wheelchair use

Serious or life-threatening causes of sores

In some cases, sores may be a symptom of a serious or life-threatening condition that should be immediately evaluated in an emergency setting. These conditions include:

  • Anaphylaxis (life-threatening allergic reaction)
  • Cellulitis (infection of the skin and underlying tissue)
  • Sepsis (life-threatening bacterial blood infection)

Questions for diagnosing the cause of sores

To diagnose your condition, your doctor or licensed health care practitioner will ask you several questions related to your sores including:

  • How long have you had the sores?
  • Have you had similar sores previously?
  • Are you experiencing any other symptoms along with your sores?
  • Are you taking any medications?

What are the potential complications of sores?

Because sores can be due to serious diseases, failure to seek treatment can result in serious complications and permanent damage. Once the underlying cause is diagnosed, it is important for you to follow the treatment plan that you and your health care professional design specifically for you to reduce the risk of potential complications including:

  • Organ failure or dysfunction
  • Severe discomfort or pain
  • Shock
  • Skin ulcerations and infections
  • Spread of cancer
  • Spread of infection
  • Vitamin deficiencies


  1. Vesicles. MedlinePlus, a service of the National Library of Medicine National Institutes of Health. http://www.nlm.nih.gov/medlineplus/ency/article/003939.htm.
  2. Cold sores. MedlinePlus, a service of the National Library of Medicine National Institutes of Health. http://www.nlm.nih.gov/medlineplus/coldsores.html.
  3. Feigin RD, Cherry JD, Demmler-Harrison GJ, Kaplan SL (Eds), Textbook of Pediatric Infectious Diseases, 6th ed. Philadelphia: Saunders, 2009.
  4. Ferri FF (Ed.) Ferri’s Fast Facts in Dermatology. Philadelphia: Saunders Elsevier, 2011.

What are sores?

A sore is a blister, bump, lesion or ulcer occurring anywhere on the body. The sore may be painful, itchy, red, swollen, or tender to the touch. The sore may be hard or filled with fluid. The surface of the sore may be broken and bleeding. Some sores may not be associated with pain.

There are numerous causes of sores, which range from mild to serious. Sores may occur as the result... Read more about soresintroduction


What other symptoms might occur with sores?

Sores may accompany other symptoms, which vary depending on the underlying disease, disorder or condition. Symptoms that frequently affect the skin may also involve other body systems.

Skin symptoms that may occur along with sores

Sores may accompany other symptoms affecting the skin including:

Medical Reviewer: William C. Lloyd III, MD, FACS Last Annual Review Date: May 7, 2013 Copyright: © Copyright 2014 Health Grades, Inc. All rights reserved. May not be reproduced or reprinted without permission from Health Grades, Inc. Use of this information is governed by the HealthGrades User Agreement.

This Article is Filed Under: Infections and Contagious Diseases

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