Encyclopedia / A / Actinomycosis



Actinomycosis is an infection caused by a bacterium called Actinomyces israelii (A. israelii).


Actinomycosis (also known as Rivalta disease, big jaw, clams, lumpy jaw or wooden tongue) is an infection, commonly of the face and neck, that produces abscesses (collections of pus) and open-draining sinuses (tracts in the skin).

Actinomycosis is caused by a bacterium called Actinomyces israelii (A. israelii). It occurs normally in the mouth and tonsils. This bacterium may cause infection when it is introduced into the soft tissues by trauma, surgery or another infection. Once in the tissues, it may form an abscess that develops into a hard red to reddish purple lump. When the abscess breaks through the skin, it forms pus-discharging lesions.

There are at least five (5) types of actinomycosis:

Cervicofacial actinomycosis occurs in the mouth, neck and head region. The bacterium enters through the periodontium (the tissues surrounding and supporting the teeth), soft tissue wounds or salivary gland ducts. It is believed that infection may arise after a tooth extraction, from tooth decay or abscess, as a part of periodontal disease, from a nonpenetrating jaw trauma, poor dental hygiene, or mucosal injuries.

Cervicofacial actinomycosis develops slowly. The area becomes hard, the overlying skin becomes reddish and swelling appears in the mouth and neck. Abscesses develop within and eventually drain to the surface where sulfur granules (yellowish gray masses), masses of filamentous (long, threadlike structure) organisms, may be found in the pus.

Thoracic actinomycosis involves the lungs and mediastinum (region between the two lungs). The disease begins with fever, cough, and sputum production. The patient becomes weak, loses weight and may have night sweats and shortness of breath. Multiple sinuses may extend through the chest wall, to the heart, or into the abdominal cavity. Ribs may be involved. Occasionally, cervicofacial and thoracic disease may result in nervous system complications - most commonly brain abscesses or meningitis.

Abdominal actinomycosis are mostly preceded by surgery such as laparotomy for acute appendicitis, perforated ulcer, or gallbladder inflammation. Infection usually begins in the gastrointestinal tract and spreads to the abdominal wall. Spiking fever and chills, intestinal colic, vomiting, and weight loss, a palpable (can be felt) mass and an external sinus are evident in this type of actinomycosis. This type of actinomycosis may be mistaken for Crohn's disease, malignancy, tuberculosis, Amebiasis (an infection of the intestine or liver), or chronic appendicitis.

Pelvic actinomycosis affects the women's pelvic area and may cause lower abdominal pain, fever, and bleeding between menstrual periods. This form of the infection has been associated with the use of IUDs (intra-uterine devices) that do not contain copper.

Generalized actinomycosis may involve the skin, brain, liver and urogenital system.


Actinomycosis may be hard to diagnose at onset. There are lab tests that may isolate actinomyces in pus or tissue specimens.


Treatment for actinomycosis is long term, generally with up to one month of intravenous penicillin G, followed by weeks to months of penicillin taken by mouth. Additionally, surgical excision and drainage of abscesses may be necessary.


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