Streptothricosis: causes, symptoms, diagnosis, and treatment

Streptothricosis is an exogenous infection often caused by trauma or inadvertently implanted pathogens, mainly invades the skin, subcutaneous tissues, and bones, and is characterized by swelling, induration, abscesses, and sinus tracts, resembling mycetoma, more common in adult males.


Causes

The pathogens include Streptomyces madurae that presents white particle in histopathology, Streptomyces somaliensis that presents brownish yellow particle in histopathology, Streptomyces pelletieri that presents red particle in histopathology, Streptomyces paraguayensis that presents black particle in histopathology, and Streptomyces albus that presents black particle in histopathology.


Signs and Symptoms

The disease mainly occurs in the feet. The initial manifestations are papules, small nodules, or induration with vesicles, followed by abscesses and sinus tracts after rupture of abscesses. Pus and particles are discharged from the sinus tracts. The infection can continue to expand and new nodules occur, causing extensive swelling and deformation of the feet. There are no obvious systemic symptoms, and local pain is unapparent. Osteolytic lesions accompanied by periosteal reaction and hyperplasia can be seen in X-ray examination. In addition, sometimes arthritis may occur.


Histopathology

The pathological changes are purulent granuloma with neutrophil infiltration. Particles can be seen in the abscesses. Different sized, different colored, different shaped particles can be seen in HE stain.


Diagnosis

The diagnosis is mainly based on the clinical manifestations and microscopy or histopathology.


Treatment

Incision and drainage or surgical resection can be used to treat early and local lesions. Sulfanilamide, penicillin, and tetracycline are also effective.