Actinomycosis is an infection with Actinomyces bacteria. It causes pus-filled wounds, usually around your face and mouth, which slowly spread to nearby tissue. It’s usually caused by dental disease or surgery, but abdominal surgeries, aspiration and IUDs can also cause it. Providers treat it with high doses of antibiotics over several months.


What is actinomycosis?

Actinomycosis (pronounced “ack-tin-oh-my-COH-sis”) is a rare bacterial infection that causes pus-filled areas (abscesses) surrounded by bumpy tissue. You get it from bacteria of the genus Actinomyces. Actinomyces live naturally in your body without harming you. But surgery, injury or disease can cause them to grow in places they don’t belong.

Actinomycosis spreads slowly into nearby tissues, usually causing a long-lasting, tunneling wound (an opening underneath your skin). The wound is filled with yellowish pus and “sulfur granules.” Sulfur granules are clumps made up of immune cells and parts of the bacteria. (They don’t actually contain sulfur — the name comes from the yellow color.)

Actinomycosis can sometimes take weeks or months to cause symptoms after the infection starts.

Types of actinomycosis

Actinomyces most commonly infect areas around your mouth and face. But you can get actinomycosis in other parts of your body, as well. Healthcare providers refer to the type of actinomycosis by the part of your body that’s infected:

  • Cervicofacial actinomycosis affects your face, mouth, nose, neck or jaw. It’s sometimes called “lumpy jaw.”
  • Thoracic or pulmonary actinomycosis affects your lungs or chest.
  • Uterine or pelvic actinomycosis affects your pelvic area and reproductive organs.
  • Abdominal actinomycosis affects your intestines or other abdominal organs.


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Symptoms and Causes

What are the symptoms of actinomycosis?

Symptoms of actinomycosis depend on where you’re infected. They can include:

  • Fever.
  • Weight loss.
  • Bumpy, fluid-filled areas on your neck, jaw or face or in your mouth (cervicofacial infection).
  • Pain when you chew or severe jaw tightness (infection in your mouth or jaw).
  • Chest pain (lung infection).
  • Abdominal pain (pelvic or abdominal infection).
  • Vaginal bleeding or discharge (pelvic infection).

Since Actinomyces grow slowly, symptoms might not develop for months or years after the surgery or illness that started the infection.

What causes actinomycosis?

Actinomyces israelii (A. israelii) bacteria are the most common cause of actinomycosis. But many other types of Actinomyces bacteria can also cause it, including A. naeslundii, A. odontolyticus, A. viscosus, A. gerencseriae and others.

Most of the time, Actinomyces live in certain mucous membranes, like your throat, intestinal tract (gut) and vagina. They’re among thousands of bacteria that live on or in your body without harming you. But if they get into a place they shouldn’t be, they’ll start reproducing and cause an infection.


How do you get actinomycosis?

You get actinomycosis when Actinomyces bacteria get into parts of your body where they don’t belong. For instance, surgery, injury or certain diseases can cause a break in a mucous membrane that allows the bacteria to infect part of your body where they don’t normally live. Foreign objects in mucous membranes can also allow bacteria to grow.

The most common way to get actinomycosis is as a result of gum disease or dental procedures. Other causes include:

Is actinomycosis contagious?

No, actinomycosis isn’t contagious. You can’t get it from someone who’s infected.

What are the risk factors for actinomycosis?

Anything that can injure tissue in your mouth, digestive tract or uterus can increase your risk for actinomycosis. This includes:

  • Diseases or conditions that damage your tissues.
  • Poor dental hygiene.
  • Implanted devices, surgeries or procedures. For IUDs, the risk increases the longer you’ve had the device in.

Experts aren’t sure why, but men and people assigned male at birth (AMAB) are at a higher risk for actinomycosis than women and people assigned female at birth (AFAB). You’re also at a higher risk if you have a compromised immune system, since you can’t fight off infections as easily.

What are the complications of actinomycosis?

If you don’t treat it or don’t complete your course of antibiotics (medication), the bacterial infection can spread and cause:


Diagnosis and Tests

How is actinomycosis diagnosed?

A healthcare provider diagnoses actinomycosis based on your symptoms and by taking a sample of fluid or tissue. A pathologist uses a microscope to look for Actinomyces or the granules it causes in the sample.

Actinomycosis is rare and can look similar to other conditions, like cancer. Sometimes, it can take a long time to diagnose it.

Management and Treatment

How is actinomycosis treated?

Healthcare providers treat actinomycosis with high doses of antibiotics. A provider usually gives you antibiotics through an IV in your arm for a few days or weeks, then you continue to take an antibiotic in pill form at home. They may also need to drain infected areas and remove dead tissue from them (debridement).

Medications that treat actinomycosis

A provider might use one of the following antibiotics to treat actinomycosis:

  • Penicillin.
  • Amoxicillin.
  • Erythromycin.
  • Tetracycline.
  • Doxycycline.
  • Minocycline.
  • Clindamycin.

How soon after treatment will I feel better?

You may need to take antibiotics for months or even a year for actinomycosis to completely go away. If you stop antibiotics too soon, the infection can come back or start spreading again.


Can actinomycosis be prevented?

You can reduce your risk of cervicofacial actinomycosis (the most common type) by taking care of your dental health. This includes:

  • Avoiding smoking and other tobacco products.
  • Brushing your teeth at least twice a day with fluoride toothpaste.
  • Flossing daily.
  • Using an antibacterial mouthwash.
  • Visiting your dentist regularly. They can spot any potential issues with your teeth and gums early.

Other forms of actinomycosis are hard to prevent, but they’re also uncommon.

Outlook / Prognosis

What can I expect if I have actinomycosis?

If you have actinomycosis, you can expect to be on antibiotics for a long period of time (several months or longer) to completely get rid of the infection. You’ll need regular follow-ups with your healthcare provider to make sure the medicine is working. You’ll also need to pay close attention to your symptoms and let your provider know right away if they’re getting worse.

What’s the outlook for actinomycosis?

The outlook (prognosis) for actinomycosis is usually good. You have the best chance of a full recovery if:

  • The infection is treated early.
  • You continue taking the entire course of antibiotics as directed by your provider.
  • You don’t have underlying immune system issues.

Can actinomycosis be fatal?

Yes, actinomycosis can be fatal. While most people with actinomycosis recover with treatment, the infection can spread if left untreated or if you stop treatment too soon. Nasal infections are particularly dangerous because they can spread to your brain.

Living With

How do I take care of myself?

The best way to take care of yourself with actinomycosis is to take all of your medication as prescribed and keep all follow-up appointments with your provider. If you stop taking antibiotics too soon, the infection can spread again and cause serious complications.

When should I see my healthcare provider?

See a healthcare provider if you have symptoms of actinomycosis or notice a wound that won’t heal or keeps spreading.

Keep in close contact with your provider while you’re still treating actinomycosis. Contact them if you have any questions or if your symptoms get worse.

When should I go to the ER?

Go to the emergency room if you have any signs of severe illness, including:

  • A fever over 103 degrees Fahrenheit or 40 degrees Celsius.
  • Severe pain.
  • Seizures.
  • Confusion or disorientation.

What questions should I ask my doctor?

It might be helpful to ask your healthcare provider:

  • How do I take care of skin wounds?
  • How long will I be on antibiotics?
  • How do I take this medication?
  • When should I follow up with you?
  • What new or worsening symptoms should I look out for?

A note from Cleveland Clinic

Harmless and even helpful bacteria live on and inside our bodies. But sometimes, harmless bacteria can get into parts of our bodies where they’re not supposed to be. When Actinomyces get in the wrong place, they can cause a long-lasting wound that spreads and damages your tissues. But with early diagnosis and treatment, you can cure actinomycosis. Treatment can take a long time and requires patience. Be sure to check in with your healthcare provider frequently. They can make sure you’re on the right antibiotics and let you know when it’s safe to stop treatment.

Medically Reviewed

Last reviewed on 05/09/2023.

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