My labrador’s ear flap has swollen up like a balloon. It doesn’t seem very sore and he has not been scratching or shaking his head. What do you think has happened?

Ciara, Strabane

It sounds like he has developed an aural hematoma, an accumulation of blood which usually appears as a fluid-filled swelling on the underside of the flap. The exact cause is poorly understood, but any condition that leads to head shaking or ear scratching, such as bacterial ear infection or ear mites, may cause it, as can a direct trauma. Some seem to appear spontaneously, and we believe these have an immunological basis. Left untreated, the swelling may eventually resolve on its own, leaving the ear deformed, a ‘cauliflower ear’. Prompt treatment can prevent this unsightly scarring. Sometimes surgery can be avoided by drainage and instillation of a potent corticosteroid into the affected flap. Sounds like he needs a trip to the vet.

My two chinchillas won’t use their dust bath.
Francis, Newtownards

In the wild, chinchillas use fine sand to keep their coats clean and in prime condition. Most love their dust bath. Maybe the shape of the bath is wrong, or perhaps the dust is irritant? Proper chinchilla dust can be purchased from most pet shops. Never use ordinary sandpit or builders’ sand as this can be too coarse and will damage the chinchilla’s fur and skin.

The bath needs to be large and deep enough for your chinchilla to roll around in without injuring itself, and the dust should be 10cm deep. Offer the bath once a day, only for about 20 minutes. If you have been leaving it in for longer than this, they may have soiled it, and they certainly won’t want to bathe in it then. Change the dust frequently: at least once a week. I think they will come round if you persevere. Good luck!