What is Canine Demodicosis?

Canine demodicosis is a skin condition in dogs caused by the parasitic mite Demodex canis. This type of mite is commensal, meaning it is typically found on dogs without causing harm, but excessive multiplication of these mites in hair follicles and sebaceous glands can lead to disease.

About 50% of adult dogs are asymptomatic carriers of Demodex mites. Dog-to-dog transmission can only occur during the first 72 hours of a puppy's life when it can acquire mites from the nursing mother. The infestation and disease are not transmissible between adult dogs, nor can it be acquired from the environment.

Demodex mites complete their entire life cycle on a single host. Signs of infestation become apparent only when mite numbers increase significantly. Two types of demodicosis are recognized: localized and generalized. The condition ranges from simple skin lesions to severe systemic signs, particularly when left untreated or with secondary bacterial infection. The face, limbs, feet/paws, and occasionally the trunk are the areas most likely to be affected.

Immunodeficiency is a predisposing factor for demodicosis. It is probably hereditary in young dogs under two years old and acquired in adult dogs due to an underlying cause such as excessive immunosuppressive therapy, Cushing's syndrome, diabetes mellitus, or neoplasia.

Demodicosis is a common but under-diagnosed medical condition in dogs that can be very serious. Since the mite is believed to be transmitted from the dam to her young during nursing, bitches that have given birth to puppies with demodicosis must be removed from breeding, and all their descendants should be monitored closely.

It is important to have excellent communication between the veterinarian and owner when treating demodicosis. Treatment duration can be long and expensive, and monitoring is essential. Owners must be motivated and given good advice by their vet. Prognosis has improved considerably in recent years with products like NexGard SPECTRA®, which effectively treats and controls Demodex mites with just one monthly chew, protecting dogs from demodectic mange.