Interdigital cysts (furunculosis) are painful, recurrent inflammatory lesions between the toes in dogs that require systematic investigation of underlying causes to prevent chronic welfare impairment.
Interdigital cysts cause significant, often underrecognised paw pain. Dogs with active furunculosis lick at the affected foot continuously, walk with altered gait to offload the painful area, and may be reluctant to walk on hard surfaces. The ruptured cysts produce bloody, purulent discharge and cause intense discomfort. Because the condition recurs without treating the underlying cause, many dogs cycle through repeated episodes of acute pain over years. The welfare toll of multiple episodes over a dog's lifetime is substantial. Thorough investigation — including skin cytology, deep skin scrapings for demodex, allergen testing, and food elimination trials — provides the information needed to break the recurrence cycle.