Aspergillosis (Nasal)

Nasal aspergillosis is a fungal infection of the nasal passages and sinuses, most often caused by a species of mould called Aspergillus fumigatus. The fungus can colonise the lining of the nose, leading to inflammation, discharge, and sometimes destruction of the delicate structures inside. It occurs most commonly in dogs, particularly those with longer noses, and is rare in cats. Owners often notice a persistent nasal discharge—sometimes clear, sometimes thick or containing blood—that may affect one or both nostrils. Sneezing, nosebleeds, or a change in the appearance of the nostril itself can also occur. The signs tend to develop gradually, and many dogs remain otherwise well in the early stages. This page explores what nasal aspergillosis may look like in practice, what is understood about how the infection takes hold, how it is investigated using imaging and sampling, and the range of approaches that exist for managing it. The goal is to help you understand what may be happening and what questions might be useful to consider.