Some pets may not show any signs but still remain a source of re-infestation for other pets. Other pets have intense pruritis (itchiness) and/or massive amounts of ear discharge. The discharge is usually brown and waxy, and often described to look like coffee grounds. One or both ears may be affected. Secondary infections with bacteria and yeasts may occur which can cause even more severe clinical signs.
In very heavy infestations mites may leave the ear canal and migrate to other parts of the body.
The presence of the brown waxy discharge is often suggestive of infestation. Your vet may also see mites by examining the external ear canal with an otoscope or by looking at an ear swab under a microscope.