Welcome on Therapeutics in Dermatology !
Actinomycosis – or actinobacteriosis – is a rare and largely poorly-understood chronic, suppurating, granulomatous and extensive infection [8, 11]. It is caused by Actinomyces, Gram-positive filamentous bacteria, obligate or facultative anaerobes, which are normal commensals in the mouth and gastrointestinal tract. In human pathology, the most commonly encountered species is A. israelii. Various factors cause Actinomyces to become pathogenic. These can be:
— local: damage to the mucosa, poor dental hygiene and foreign bodies (for instance, a hip prosthesis or prolonged use of an intrauterine device);
— or systemic: immunosuppression, cancer, diabetes, alcoholism and smoking.
There are many clinical presentations of actinomycosis, and it has the potential to affect any of the organs. It may share some features with other diseases such as tuberculosis, lung cancer, colorectal cancer, Crohn’s disease and gynaecological cancers, etc. Whatever the starting point, the infection tends to spread to the adjacent organs without respecting anatomical barriers, and to fistulise, either in a hollow cavity or on the skin.
Cervicofacial actinomycosis is the most common clinical form (55 %) [6, 7]. The infection starts as a result of the damage to the oral mucosa, gums or pharynx and is promoted by poor oral hygiene or a wound in the mouth. Typically, patients present with a painless, subcutaneous, fluctuating swelling with a subacute or chronic course, most often in the jaw area. Satellite adenopathies are rare. Left untreated, multiple cervicofacial masses with a pseudo-tumoural appearance may form, potentially spreading to the periostium and mandible.
Abdominal actinomycosis accounts for 25% of cases [5, 9]. It is most commonly a complication of appendicitis . Thoracic actinomycosis (15 to 20 %) most often arises subsequent to inhalation of Actinomyces from the oropharyngeal cavity . The lesions mimic tuberculosis but are localised essentially in the lower lobes of the lungs. Pelvic involvement is reported in women who have an intrauterine device [3,10].
The infection spreads to the skin via three possible mechanisms: by contiguity as is the case with cervicofacial actinomycosis, by blood-borne dissemination from a pulmonary focus or by direct inoculation in damaged skin (exceptional).
Lastly, actinomycosis may present in disseminated form, spread by the blood and creating lesions in the skin, vertebrae and visceral organs.
× N.B. : This limited content is for the general public. If you are a health professional, click here to register for free and gain access to a dedicated deeper content.
If you already have an account, log in!
Therapeutics in Dermatology, Fondation René Touraine © 2001-2012