Definition & Overview

The feet and ankles are prone to a variety of medical conditions and one of the most common is infection, which is typically caused by wounds that were left untreated, surgery, and other factors such as bacteria. Depending on the severity of these conditions, they may result in a person becoming temporarily or permanently disabled, the loss of a limb, or even death.

Infections occur when a pathogen enters the body, usually through an open wound in the skin, and begins to colonize the host. Some of the most common pathogens are bacteria, fungi, parasites, and prions.

The body has a defence mechanism against infections called the immune system. However, it can sometimes weaken and thus unable to fight the pathogens and the spread of infection. Infections, not only affect the muscles and tissue but also the bones, joints, bursa, and blood.

Cause of Condition

The primary cause of an infection is a break in the skin that serves as the gateway for pathogens to enter the body. However, not all pathogens require wounds to invade the body. For instance, fungi can build up on the skin surface and slowly eat their way through the skin. Parasites can attach themselves to the skin and start an infection from there. Arthritis is an infection of the joints caused by germs that travelled through the bloodstream from other parts of the body.

Some of the most common infections of the foot and ankles are

  • Athlete’s foot – caused by fungus
  • Warts – a viral infection of the skin
  • Bacterial infections caused by staphylococcus and streptococcus bacteria

Diabetes is also a common cause of foot and ankle infections as it weakens the immune system. Thus, wounds on the feet caused by a breakdown of corn and calluses can easily be penetrated by bacteria. Statistics shows that one of the top reasons why diabetes patients visit the hospital is because of a foot infection.

Key Symptoms

An infection only occurs if the pathogen harms the body. For instance, a number of bacteria reside in the stomach, but since most of them do not harm the body, they do not result in an infection. If the pathogen begins to cause widespread infection, the most common signs are increased pain and swelling in the affected area. The area, usually a wound, will be tender and appear red. In some cases, blood can clot and make it appear the wound is healing, but the infection has already begun to spread to the inner layers of the skin and abscess begins to form.

Inflammation is also a common sign of an infection. If the infection begins in the skin, the affected area will be inflamed. If the infection affects the bone or joints, a larger portion of the affected foot will be swollen.

It’s important to understand that inflammation does not necessarily mean the presence of an infection. Some good examples are gout, rheumatic diseases, and an injury to the bone or joint. These conditions are not infections, but they do cause inflammation.

Who to See and Types of Treatment Available

Patients who are suffering from a foot or ankle infection are strongly advised to see their primary doctors as soon as possible as infections can spread rather quickly. The more they spread throughout the body, the harder they are to treat. In fact, if the infection travels through the bloodstream, it can result in a condition called sepsis, which is an infection of the entire body.

During the consultation, the doctor will examine the feet and review the patient’s medical history. Not all infections will require treatment using medications. If the immune system is strong, it will usually be enough to fight off a minor infection. More serious infections will be treated using antibiotics.

People with foot and ankle infections who are known diabetics should consult an endocrinologist. Diabetes results in a variety of foot infections, such as cellulitis and chronic osteomyelitis. Cellulitis is easier to cure because the infection does not result in circulation problems allowing medications to reach the affected site easier. On the other hand, chronic osteomyelitis requires a surgical procedure.


  • Canale, S. Campbell's Operative Orthopaedics, Mosby Elsevier, 2007.
  • Goldman, L. Cecil Medicine, Saunders Elsevier, 2008.
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