Actinomycosis is a rare, infectious disease in which bacteria spread from one part of the body to another through body tissues. Over time, it can result in linked abscesses, pain, and inflammation.

It can affect the skin or deeper areas within the body and sometimes the blood.

Many people have actinomycosis bacteria in their body, but the bacteria usually stay in one place and do not cause disease in healthy tissues.

If damage occurs in the area around where the bacteria live, due to injury or trauma, the bacteria can move to other areas.

As the condition progresses, the deep tissue can become inflamed and pus-filled. It can result in abscesses, tissue death, cavities, and masses of fibrous tissue in the body.

According to an article published in Clinical Microbiology Reviews, infection is not contagious, because these bacteria cannot survive outside the human body and infections typically occur after tissue damage.

Find out more about actinomycosis and the treatment options available.

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Actinomycosis is a rare infection that can spread through body tissues.

Actinomycosis happens when the Actinomyces species of bacteria spread through the body because of tissue damage.

Most people have Actinomyces bacteria in the lining of the mouth, throat, digestive tract, and urinary tract, and it is present in the female genital tract.

The bacteria live harmlessly in the body, but they become dangerous if they spread out of their usual environment.

This can happen as a result of:

  • disease
  • tissue damage due, for example, to injury or surgery

If something sharp pierces the internal body tissues, such as a fish bone in the esophagus, the bacteria can spread.

Actinomycosis can also happen if there is tooth decay or gum disease.

As the infection progresses, painful abscesses can form and grow in size. This usually takes several months.

Sometimes, it can be so severe that the infection enters the surrounding bone and muscle. In severe cases, the skin can break open, leaking large amounts of pus.

Actinomyces bacteria are anaerobic. This means they live deep inside body tissues, where oxygen levels are very low.

This type of bacterial infection can be harder to diagnose and often takes longer to treat than other types.

Actinomycosis can affect almost any part of the human body.

Jaw or mouth

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A mouth or gum infection can lead to actinomycosis.

Orocervicofacial actinomycosis affects the mouth, jaw, or neck. The bacteria that cause this infection typically live in dental plaque.

It can result from:

  • dental problems, such as decay and poor oral hygiene
  • trauma to the mouth or face, if particles of dental plaque enter the mucous membrane

It can also develop after a dental procedure.

The person may notice the infection within hours of injury, or it may take several weeks for symptoms to appear.

There may be:

  • a hard, painful swelling in the soft tissue of the mouth, known as a “woody” fibrosis
  • an abscess

This is the most common form of infection caused by Actinomyces. It accounts for 50 percent of all cases, according to an article published in Antimicrobe.


Thoracic actinomycosis can develop in the airways and lungs.

It often happens when people breathe bacteria from the mouth and throat into the lungs.

The symptoms affect the lungs first. Then they can extend to the area around the lungs, the chest cavity, and the upper spine.

The person may experience:

  • weakness
  • a fever
  • a productive cough
  • severe weight loss


Abdominal actinomycosis occurs in the abdomen, but it can affect any part of the digestive system, from the food pipe to the anus.

It can happen after an appendix bursts, or after a person has surgery for appendicitis.

The individual may have:

The type of infection can spread.

It can reach

  • the pericardium, which is the sac around the heart
  • the liver or spleen

Sometimes, it can go on to affect the pelvis.


Pelvic actinomycosis can spread from the vagina to other areas in the pelvis. Certain gynecological procedures can increase the risk.

Sometimes, using an intrauterine device (IUD) for birth control for a long time can increase the chance of developing this type of infection.

If this occurs, the individual may notice:

  • vaginal discharge
  • pain or a lump or swelling in the lower abdomen or pelvis

The American College of Obstetricians and Gynecologists (ACOG) note that around 7 percent of women with an IUD have Actinomyces bacteria, usually without symptoms. Tests usually find the bacteria by chance.

ACOG guidelines published in 2016 recommend that the IUD can remain in place for its recommended time of use. No treatment is necessary.

However, people should not leave an IUD in place longer than recommended. Depending on the type, this may be 5 or 10 years.

The bacteria can also cause abscesses in the ovaries and fallopian tubes. These can lead to complications with other organs within the abdomen and pelvis.

Anyone with an IUD who experiences pain or discomfort or signs of a fever should see a doctor.

Rare types of actinomycosis

Without treatment, actinomycosis can affect the central nervous system (CNS). This is rare.

It can happen directly due to a lesion on the neck or face, or it may spread from elsewhere. It can lead to a brain abscess, causing headaches and neurological symptoms.

Another rare type affects the skin and bones, usually when the infection spreads from deeper tissues.

Actinomycosis can take a variety of forms. It can also resemble other infections, and even neoplasms, or tumors.

It typically features a number of small, interlinked abscesses.

The symptoms depend on the type of actinomycosis, but they may include:

  • swelling and inflammation at the site of the infection
  • tissue damage and scar tissue
  • abscesses, or pus-filled lumps
  • small holes or tunnels in tissue called fistulas that can leak a kind of lumpy pus

The severity of symptoms mostly depends on where in the body the infection occurs

There may be pain and fever, along with body aches, fatigue and a general feeling of being unwell.

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Lab tests of sputum, pus, or tissue may be necessary to diagnose actinomycosis.

To diagnose actinomycosis, a doctor may take a sample of sputum, pus, or tissue to send for microscopic investigation in a laboratory. Sometimes, the laboratory will make a culture of the bacteria.

If the infection is present, the pus or tissue will usually contain yellow sulfur granules.

In some cases, the abscess may resemble a cancerous growth. Lesions in the lungs can cause symptoms similar to cancer or tuberculosis (TB).

It is important to rule out other causes of similar symptoms.

Actinomycosis can persist for a long time. Long-term treatment with antibiotics, such as penicillin, is common. It may last from 8 weeks to over 12 months.

In some cases, a surgeon may drain an abscess or remove an infected part. After this, the person may need a 3-month course of antibiotics to resolve the problem.

Actinomycosis develops slowly, but it can have a serious impact on a person’s health. It is important to get early treatment if it occurs.

Authors of a study published in 2014 suggest the following ways of reducing the risk of developing actinomycosis:

  • avoiding alcohol abuse
  • maintaining good overall health
  • keeping long-term medical conditions under control
  • practicing good dental and oral hygiene

In countries with good access to antibiotics and dental services, the chance of having actinomycosis tends to be lower.