Blastomycosis in a dog that has travelled: treatment and prognosis
4-year-old Pointer that spent the summer with its owner by lakes in Ontario (Canada). It now has a cough, tachypnoea, a diffuse nodular lung pattern, draining skin lesions and uveitis. Exudate cytology shows large, thick-walled yeasts with broad-based budding. Itraconazole is started.
Which statement about its treatment and prognosis is correct?
chevron_right Show answer and explanation
A. It is transmitted by the respiratory route and the dog must be isolated from the family
Blastomyces is acquired by inhaling spores from moist soil; the tissue yeast form is not airborne. The family's risk comes from having shared the same environment.
B. 7–10 days of itraconazole are enough if signs improve
It is a deep mycosis: treatment lasts a minimum of about 2 months and continues for at least a month after signs resolve; short courses are associated with relapse.
C. The uveitis always responds well because itraconazole penetrates the eye very well
Ocular penetration of antifungals is limited, and severe posterior segment involvement often leaves a blind, painful eye that may require enucleation to remove a reservoir of infection.
D. In the first days respiratory function may worsen due to the inflammation caused by fungal death, and severe lung involvement is the main negative prognostic factor
Correct. Mass death of organisms in the lung triggers an inflammatory reaction that can worsen dyspnoea at the start of treatment, and this is when most deaths occur. With mild lung involvement the prognosis is much better.
lightbulb Key takeaway
Blastomycosis is not endemic in Spain: suspect it in dogs that have been to North America, especially near rivers and lakes. Veterinarians can be infected by needlestick injuries or bites, so handle lesions and samples with gloves.
Test yourself with 10 random questions
Infectious diseases · 100 questions, a different test every time
Related questions
Updated: October 31, 2026 · Educational content for veterinary professionals. It does not replace current clinical guidelines or the judgement of the attending veterinarian.