What are the other Names for this Condition? (Also known as/Synonyms)

• Skin Actinomycosis

What is Cutaneous Actinomycosis? (Definition/Background Information)

• Cutaneous Actinomycosis is a rare and chronic skin infection, caused predominantly by the bacterium Actinomyces israelii and to a lesser extent by other Actinomyces species. It may be caused by a break in the skin, which possibly allows access to pathogenic bacteria to initiate infection
• They exist naturally in the mucous lining of the nose, throat, mouth, digestive tract, and female reproductive tract, and are not normally harmful. These anaerobic bacteria have the ability to grow in the absence of oxygen, or in reduced concentrations of oxygen
• However, any injury, trauma, or surgical procedure can cause the bacterial cells to enter deeper tissues, where they are not normally found. Since these bacteria can grow without oxygen, they can thrive in such environments, resulting in infection
• Most infections, about two-thirds, occur on the face and neck. The other main sites of occurrence are pulmonary, gastrointestinal, and pelvic. The symptoms of the condition include formation of nodules on skin, which may or may not be inflamed. There may be drainage of pus from the abscess
• Examination of the fluid drainage under microscope and culture of affected tissue specimen and imaging techniques may be employed to diagnose Cutaneous Actinomycosis. The pus or drainage is checked for “sulfur granules”. These granules do not contain sulfur, but are colonies of the organism visible to the naked eye. The clumps superficially resemble granules of elemental sulfur 
• Prolonged treatment with antibiotics is necessary to remove the infection. In some cases, the abscess may be surgically drained or removed. With a prompt diagnosis and sustained treatment, Cutaneous Actinomycosis is curable

Who gets Cutaneous Actinomycosis? (Age and Sex Distribution)

• Cutaneous Actinomycosis is a rare and chronic infection, reported from several parts of the world
• This infection may affect individuals of all ages and both genders

What are the Risk Factors for Cutaneous Actinomycosis? (Predisposing Factors)

The following are some known risk factors for Cutaneous Actinomycosis:

• Injury to skin that is left unattended
• Poor dental hygiene
• Malnutrition
• Certain pre-existing conditions such as uncontrolled diabetes
• Compromised immunity owing to HIV/AIDS, organ transplantation, chemotherapy or radiation therapy

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Cutaneous Actinomycosis? (Etiology)

Cutaneous Actinomycosis is caused by anaerobic bacteria, belonging to the family Actinomycetaceae. These bacteria are gram-positive and can survive in very low concentrations of oxygen. The following are some bacterial species known to cause actinomycosis:

• Actinomyces israelii, which is responsible for majority of infections
• Actinomyces gerencseriae
• Actinomyces viscosus
• Actinomyces meyeri
• Actinomyces naeslundii

Under normal circumstances, the bacteria are present in the mucous lining of the mouth, throat, digestive system, and the female reproductive tract, without causing harm.

• However, when the mucous lining gets damaged owing to numerous factors, such as injury, trauma, or surgery, the bacteria enter the inner/deeper tissues
• In particular, many of the cervicofacial infections are preceded by dental trauma
• Being anaerobic, they can survive and multiply in the low oxygen conditions of deep tissue, causing the development of scar tissue and fistula (or abnormal tracts)
• Abscess formation can take place with the accumulation of pus, which may drain when the tracts reach the surface of skin. This process may take months to years

The exact mechanism of infection in Cutaneous Actinomycosis is not known. It is believed that a cut or break in the skin may lead to the bacterial invading the deeper skin layers.

Note: The condition is not contagious and it does not spread from one individual to another.

What are the Signs and Symptoms of Cutaneous Actinomycosis?

The signs and symptoms of Cutaneous Actinomycosis may include the following:

• Inflammation of skin
• Abscesses on skin, with or without inflammation
• Drainage of pus from the abscess
• Any part of the body skin, such as the external ear, chest wall, forehead, pelvis, or buttocks may be affected

How is Cutaneous Actinomycosis Diagnosed?

Cutaneous Actinomycosis is diagnosed on the basis of the following tests and exams:

• A thorough physical examination and assessment of symptoms
• Evaluation of the affected individual’s medical history
• Microscopic observation of pus or tissue samples, to check for the presence of sulfur granules (which are round and yellow, and are named for their characteristic appearance; but, they do not contain sulfur). The tissue samples may have to be obtained surgically
• Culture of fluid or tissue from infected area: These bacteria are slow to grow in culture, and it may take over 3 weeks to obtain a (positive) culture result
• X-ray, computed tomography (CT), or magnetic resonance imaging (MRI) scans of the affected area, to ascertain location and number of abscesses, as well as differentiate inflammatory masses due to infection from the tumors

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Cutaneous Actinomycosis?

The following are some potential complications from Cutaneous Actinomycosis:

• Formation of large lesions
• The infection spreading to other organs away from the primary site of infection
• Scar tissue formation
• Cellulitis
• Disfigurement causing cosmetic concerns and emotional stress

How is Cutaneous Actinomycosis Treated?

The treatment measures for Cutaneous Actinomycosis may include:

• Prolonged use of antibiotics (6 weeks of intravenous treatment, followed by 4 months of oral antibiotic treatment). typically, β-lactam (such as penicillin, amoxicillin) or tetracycline family of antibiotics are used
• Surgical drainage of abscess; draining the abscess by inserting a needle
• Surgical removal of infected tissue:
  • Surgery is sometimes necessary for cases in which large abscesses have developed, the infection has spread to organs and bones, and antibiotics alone are unsatisfactory
  • Surgery creates an aerobic environment, which is detrimental to bacterial growth. It also allows for the excision of lesions, drainage of sinuses, as well as containment and elimination of the disease
• Hyperbaric oxygen therapy to eliminate bacteria:
  • This therapy helps increase the concentration of oxygen in the infected tissues
  • The presence of oxygen results in higher amounts of oxygen-derived radicals that harm, and are specifically drawn to anaerobic organisms, such as Actinomyces
  • This method has only been approved as an adjunct to other forms of treatment

How can Cutaneous Actinomycosis be Prevented?

Cutaneous Actinomycosis can be prevented through adherence to the following factors:

• Practicing proper hygiene: Maintaining good oral hygiene, general skin hygiene (washing hands and body regularly), and keeping skin injury sites clean
• Maintaining good control of diabetes
• Educating oneself or monitoring self for any signs of discomfort following a surgery, and promptly reporting to the attending healthcare provider, so that infections may be detected early and treated appropriately

Completing the full course of prescribed antibiotics regimen, to eliminate the infection causing bacteria from deep tissue, as well as to prevent relapse of infection and development of drug-resistant bacterial species.

What is the Prognosis of Cutaneous Actinomycosis? (Outcomes/Resolutions)

The prognosis of Actinomycosis is usually good in healthy individuals, with early diagnosis and prompt treatment.

• The outcomes may be influenced by underlying medical conditions and/or compromised immunity
• Additionally, a lack of treatment may allow the infection to spread to other organs and tissues, which may prolong the treatment and recovery process

Additional and Relevant Useful Information for Cutaneous Actinomycosis:

Actinomycosis commonly occurs in animals (mostly cattle) and rarely in humans. In cattle, the bacteria target areas around the head, especially the jaw, which gives rise to the name “big/lumpy jaw”.