Actinomycosis

Page last reviewed: 13/07/2011

Actinomycosis is a rare type of bacterial infection. Most bacterial infections are confined to one part of the body because the bacteria are unable to penetrate through the body's tissue. However, actinomycosis is unusual in that the infection is able to move slowly but steadily through the body's tissue.

Symptoms of actinomycosis include:

  • swelling and inflammation of affected tissue
  • tissue damage that results in scar tissue
  • formation of abscesses (pus-filled swellings)
  • small holes or tunnels that develop in tissue and leak a type of lumpy pus

Actinomyces bacteria

Actinomycosis is caused by a family of bacteria known as actinomyces bacteria. In most cases, the bacteria live harmlessly on the lining of the mouth, throat, digestive system and the vagina (in women).

The bacteria only pose a problem if the tissue lining becomes damaged by injury or disease, allowing the bacteria to penetrate deeper into the body. This is potentially serious because the actinomyces bacteria are anaerobic bacteria, which means they thrive in parts of the body where there are low levels of oxygen, such as deep inside human tissue.

However, one advantage of the fact that actinomyces bacteria are anaerobic is that they cannot survive outside the human body. This means that actinomycosis is not a contagious condition.

Types of actinomycosis

In theory, actinomycosis can develop almost anywhere inside the tissue of the human body. But the condition tends to affect certain areas of the body and can be classified into four main types:

  • oral cervicofacial actinomycosis
  • thoracic actinomycosis
  • abdominal actinomycosis
  • pelvic actinomycosis

These are described below.

Oral cervicofacial actinomycosis

Oral cervicofacial actinomycosis is where the infection develops inside the tissue of the neck, jaw or mouth. Most cases are caused by dental problems, such as tooth decay.

Oral cervicofacial actinomycosis is the most common type of actinomycosis and accounts for an estimated half of all cases.

Thoracic actinomycosis

Thoracic actinomycosis is where the infection develops inside the lungs or associated airways. It is thought that most cases of thoracic actinomycosis are caused by people accidentally inhaling droplets of contaminated fluid into their lungs.

Thoracic actinomycosis accounts for an estimated 15-20% of cases.

Abdominal actinomycosis

Abdominal actinomycosis is where the infection develops inside the abdomen (tummy). This type of actinomycosis can have a range of potential causes. It can develop as a secondary complication of a more common infection, such as appendicitis, or after accidentally swallowing a foreign object, such as a chicken bone containing the actinomyces bacteria.

Abdominal actinomycosis accounts for an estimated 20% of all cases.

Pelvic actinomycosis

Pelvic actinomycosis is where the infection develops inside the pelvis (the bony structure that includes the hip bones). Pelvic actinomycosis usually only occurs in women because most cases are caused when the actinomyces bacteria are spread from the female genitals into the pelvis.

It is thought that most cases of pelvic actinomycosis are associated with the long-term use of the intrauterine device (IUD) type of contraceptive, which is often referred to as the coil. The coil is a T-shaped device that fits inside the womb.

Pelvic actinomycosis accounts for an estimated 10% of all cases.

How common is actinomycosis?

Actinomycosis is one of the rarest types of bacterial infections. It is thought that, in developed countries, just one person in every 300,000 will develop actinomycosis in any given year.

Actinomycosis is probably more widespread in parts of the world where access to antibiotics is limited and dental hygiene standards are poor. However, it is difficult to estimate the extent of the condition worldwide because reliable data are not easy to obtain.

Three out of every four cases of actinomycosis affect men, who are usually between 20 and 60 years of age. The reasons for this are unclear.

Outlook

The infection responds well to treatment, although it is usually necessary to take a course of antibiotics lasting for several months to ensure that all the bacteria are wiped out.

In some cases of actinomycosis, minor surgery may be required to repair the damaged tissue and to drain pus out of the abscesses.

Antibiotics
Antibiotics are medicines that can be used to treat infections caused by micro-organisms, usually bacteria or fungi. For example amoxicillin, streptomycin and erythromycin.
Bacteria
Bacteria are tiny, single-celled organisms that live in the body. Some can cause illness and disease and some others are good for you.
Chronic
Chronic usually means a condition that continues for a long time or keeps coming back.
Lungs
Lungs are a pair of organs in the chest that control breathing. They remove carbon dioxide from the blood and replace it with oxygen.
Tissues
Body tissue is made up of groups of cells that perform a specific job, such as protecting the body against infection, producing movement or storing fat.

Page last reviewed: 13/07/2011

Oral cervicofacial actinomycosis

The symptoms of oral cervicofacial actinomycosis include:

  • swollen lumps on your cheek or neck, which can gradually increase in size and number
  • reddish or bluish coloured skin over the lumps
  • a high temperature (fever) of 38°C (100.4°F) or above may occasionally develop

During the initial stages of oral cervicofacial actinomycosis, the lumps may be tender before later becoming painless and hard to the touch. Your jaw muscles may also be affected, which can make chewing difficult.

Oral cervicofacial actinomycosis can also cause narrow passages to open up in the surface of your skin in the affected areas. The passages are called sinus tracts. These should not be confused with sinuses, the cavities found in your face and nose.

The sinus tracts leak pus, which may contain a yellow, granular lumpy material.

Thoracic actinomycosis

The symptoms of thoracic actinomycosis include:

  • high temperature (fever) of 38°C (100.4°F) or above
  • weight loss
  • tiredness (fatigue)
  • loss of appetite
  • shortness of breath
  • chest pain
  • the appearance of sinus tracts on the surface of your chest

You may also develop a dry cough or a cough that produces phlegm. You may bring up drops of blood when you cough, or if you produce phlegm it may be blood-stained.

Abdominal actinomycosis

The symptoms of abdominal actinomycosis include:

  • mild fever, usually a temperature that is no higher than 38°C (100.4°F)
  • weight loss
  • tiredness (fatigue)
  • a change in your bowel habits, such as constipation or diarrhoea
  • abdominal (tummy) pain
  • nausea (feeling sick)
  • vomiting
  • a noticeable mass or lump in your lower abdomen
  • the appearance of sinus tracts on the surface of your abdomen

Pelvic actinomycosis

The symptoms of pelvic actinomycosis include:

  • lower abdominal pain
  • irregular or abnormal vaginal bleeding or discharge
  • loss of appetite
  • tiredness (fatigue)
  • mild fever
  • a noticeable mass or lump in your pelvis (the bony structure that includes the hip bones)
Abscesses
An abscess is a lump containing pus, which is made by the body during infection.
Tissue
Body tissue is made up of groups of cells that perform a specific job, such as protecting the body against infection, producing movement or storing fat.

Page last reviewed: 13/07/2011

Actinomycosis is caused by a strain of bacteria called actinomycetales. Actinomycetales are found in many of the body's cavities, such as inside the mouth and, less commonly, the bowel.

In women, they can also be found in the womb and the fallopian tubes (through which eggs are released into the womb). 

How actinomycosis spreads

Actinomycetales are anaerobic bacteria, which means they cannot survive in oxygen-rich environments. Therefore, they do not cause illness when they are in one of the body's cavities, such as the mouth or the intestinal tract.

However, if actinomycetales break through the protective lining (mucous membrane) surrounding the cavities, they can penetrate deep into your body's tissue. As the deep layers of human tissue are low in oxygen, the bacteria are able to reproduce quickly and infect healthy tissue.

Abscesses

In an attempt to combat the infection, your immune system (the body's natural defence against infection and illness) will send infection-fighting cells to the source of the infection. However, these cells do not have the ability to kill the bacteria and will quickly die.

As the infection-fighting cells die, they accumulate into a yellowish-coloured liquid called pus. Having failed to kill the infection, your immune system will attempt to limit its spread by using healthy tissue to form a protective barrier around the pus. This is how a pus-filled swelling, known as an abscess, is formed.

Unfortunately, the actinomycetales strain of bacteria has the ability to penetrate the protective barrier of an abscess and move into more healthy tissue. Your immune system will attempt to counter the infection by producing more abscesses.

Sinus tracts

Your body will eventually need to get rid of the accumulation of pus. To do this, small channels called sinus tracts will develop that lead from the abscesses to the surface of your skin.

The sinus tracts will leak pus, as well as 'sulphur granules', which are a yellow, powdery substance. The sulphur granules are actually made up of lumps of bacteria, but they are known as sulphur granules as they are the same colour as the chemical sulphur.

Opportunistic infection

Actinomycosis is an opportunistic infection that does not cause any symptoms unless an opportunity arises for it to penetrate into the body's tissue.

Oral cervicofacial actinomycosis

Opportunities for oral cervicofacial actinomycosis include:

Thoracic actinomycosis

Most cases of thoracic actinomycosis are thought to be caused by small particles of food or other ingested material that get mixed up with the actinomycosis bacteria. Rather than passing harmlessly down into the stomach, the particles are mistakenly passed down into the windpipe and the airways of the lungs.

People with long-term drug or alcohol problems are particularly at risk of developing thoracic actinomycosis for two reasons:

  • being drunk or intoxicated increases your risk of accidentally ingesting material into your lungs
  • long-term drug and alcohol misuse weakens the immune system, which makes a person more vulnerable to developing an infection

See the Health A-Z topics for more information about Drug misuseand Alcohol misuse.

Abdominal actinomycosis

Abdominal actinomycosis occurs when something tears the wall of the intestine (bowel), allowing the bacteria to penetrate into deep tissue.

The intestine can tear as a result of an infection, such as a burst appendix that damages the wall of the intestine. Or it can be damaged through injury, for example, when someone mistakenly swallows a fish bone.

There have also been some reported cases of abdominal actinomycosis occurring as a complication of bowel or abdominal surgery.

Pelvic actinomycosis

Most cases of pelvic actinomycosis have been recorded in women who were using the intrauterine device (IUD) form of contraception. The IUD is a small, T-shaped contraceptive device made from plastic and copper that fits inside the womb. The women affected tend to be long-term users of the IUD (eight years or more).

One explanation for the high number of cases of pelvic actinomycosis in women who are using the IUD is that, over time, the IUD may damage the womb lining, allowing bacteria to penetrate into deep tissue. However, no research has yet been done to find out whether or not this is the case.

It should be stressed that developing pelvic actinomycosis as a result of using an IUD is very unlikely. Millions of women use the IUD device and there have only been a handful of reported cases of pelvic actinomycosis.

Abscess
An abscess is a lump containing pus, which is made by the body during infection.
Bacteria
Bacteria are tiny, single-celled organisms that live in the body. Some can cause illness and disease and some others are good for you.

Page last reviewed: 13/07/2011

In its initial stages, actinomycosis can be a challenging condition to diagnose correctly. This is because it shares the symptoms of many more common conditions, including:

Because actinomycosis can be difficult to diagnose, many cases are only discovered when doctors are carrying out tests or surgery to check for the presence of other conditions. For example, many cases of actinomycosis are detected when biopsies are carried out to check for cancer. A biopsy is where a small tissue sample is removed so that it can be examined under a microscope.

Actinomycosis can usually be more confidently diagnosed in its later stages, after the sinus tracts have appeared in the surface of the skin. This is because the sulphur granules that are produced by the sinus tracts during an actinomycosis infection have a distinctive shape that can be identified under a microscope. 

Abscesses
An abscess is a lump containing pus, which is made by the body during infection.
Bacteria
Bacteria are tiny, single-celled organisms that live in the body. Some can cause illness and disease and some others are good for you.

Page last reviewed: 13/07/2011

Antibiotics

Antibiotics are the main treatment for actinomycosis. A long-term course of antibiotics is required to wipe out the infection completely.

An initial course of antibiotic injections is usually recommended for 2-6 weeks, followed by a course of antibiotic tablets for another 6-12 months.

A nurse should be able to teach you how to administer the antibiotic injections in your own home so you do not need to stay in hospital for the duration of the course.

The preferred antibiotics for treating actinomycosis are benzylpenicillin, which is used for the antibiotic injections, and phenoxymethylpenicillin tablets.

Side effects of these penicillins include:

  • diarrhoea
  • nausea (feeling sick)
  • skin rash
  • increased vulnerability to fungal infections, such as thrush (a fungal infection that occurs in the mouth)

If you are allergic to penicillin, alternative antibiotics, such as tetracycline or erythromycin can be used.

Surgery

Occasionally, surgery may be required to repair any tissue damage or to drain the pus from any abscesses that have formed deep inside your body.

Abscesses
An abscess is a lump containing pus, which is made by the body during infection.
Antibiotics
Antibiotics are medicines that can be used to treat infections caused by micro-organisms, usually bacteria or fungi. Examples include amoxicillin, streptomycin and erythromycin.
Bacteria
Bacteria are tiny, single-celled organisms that live in the body. Some can cause illness and disease and some others are good for you.
Vein
Veins are blood vessels that carry blood from the rest of the body back to the heart.

Page last reviewed: 13/07/2011

Abscesses that occur as a result of actinomycosis may develop in many parts of your body, including your lungs. Abscesses can spread easily from one part of your body to another.

If the original site of the infection is located in the skin of your face, it may spread to nearby parts of your body, such as your scalp or ears.

If the original site of the infection is your mouth, it may spread to your tongue, larynx (voicebox), trachea (windpipe), salivary glands and the tubes that connect your throat to your nose.

If the infection spreads to your brain, a brain abscess could develop. See the Health A-Z topic about Brain abscesses for more information about this type of abscess. 

Abscesses
An abscess is a lump containing pus, which is made by the body during infection.
Tissue
Body tissue is made up of groups of cells that perform a specific job, such as protecting the body against infection, producing movement or storing fat.  

Page last reviewed: 13/07/2011

Good oral hygiene

Most cases of oral actinomycosis occur as a result of poor dental hygiene. Practising good dental hygiene is the best way to prevent actinomycosis. You may find the advice listed below useful.

  • Brush your teeth twice a day using fluoride toothpaste.
  • Floss your teeth once a day.
  • Use a mouthwash that contains fluoride once a day.
  • Limit the amount of sweet and sticky food that you eat because this increases your risk of developing tooth decay.
  • Make sure that you attend all of your scheduled dental check-ups. If you have healthy teeth, you should have a dental check-up at least once every two years. However, if you have a history of dental disease, you may require more frequent check-ups.
Chemotherapy
Chemotherapy is the treatment of an illness or disease with a chemical substance, for example in the treatment of cancer.
Immune system
The immune system is the body's defence system, which helps protect it from disease, bacteria and viruses.

Content provided by NHS Choices www.nhs.uk and adapted for Ireland by the Health A-Z.

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