Blastomycosis-like pyoderma: causes, symptoms, diagnosis, and treatment

Blastomycosis-like pyoderma is a rare chronic proliferative and reactive pyoderma secondary to bacterial infection of the skin, with clinical manifestations similar to blastomycosis, more common in persons with malnutrition, chronic alcoholism, and other immune dysfunction.


Blastomycosis-like pyoderma is caused by abnormal reactions of the body against staphylococcus aureus, hemolytic streptococcus or pseudomonas aeruginosa infection.

Signs and Symptoms

Skin lesions often occur in the trauma, but new lesions can occur in normal skin later. Skin lesions can gradually expand to all directions, forming annular verrucous plaques, with raised edge, with thick crust. After removal of crust, many abscesses are visible, and pus is exuded, leaving scars after healing. Skin lesions are similar to blastomycosis but mostly solitary.


Pseudoepitheliomatous hyperplasia in the epidermis is visible, with lymphocytes and neutrophils moving into the epidermis. Granulomas and moderate neutrophil and lymphocyte infiltration in the dermis can be seen.


Diagnostic considerations include:

  • Large verrucous plaques, purulent secretions on the surface, and raised edge
  • Pseudoepitheliomatous hyperplasia in histopathology
  • At least one pathogen detected, such as staphylococcus aureus, streptococcus hemolyticus or pseudomonas aeruginosa
  • All negative results in deep fungi, nontuberculous mycobacteria, and mycobacterium tuberculosis culture
  • Negative results in fungal serum test
  • Absence of a history of oral bromine, normal bromine levels in serum


Topical detergents, such as 0.02% nitrofurazone solution or 1:5000 potassium permanganate solution, and topical antibiotic ointments, such as mupirocin ointment, can be applied. Systemic antibiotics can be administered.