Basically Itraconazole is more wide spectrum and less toxic than ketoconazole and has been hence
used for a variety of fungal infections chief being aspergillus, blastomycosis, sporotrichosis, histoplasmosis, and onychomycosis and ketoconazole is often used for Candida, Histoplasma, Coccidioides, and Blastomyces (although it is not active against Aspergillus).