Causes and Concern of Demodicosis in dogs

Dr A Sangaran
Dr Neelakshi Deka
Skin diseases have always been a matter of concern for pet parents. Awful modulation of the skin makes the animal unpleasant in appearance and also to mingle with. Amidst the various causes of skin diseases, external parasitic infections hold a good share of the cause and Demodicosis a major concern.
Demodex has never failed to grab the attention of pet parents as they infest any dog irrespective of age, sex, immunity, breed, etc. Breeds such as Afghan Hound, Terrier, Boxer, Collie, Chihuahua, Dalmatian, Bulldog, German Shepherd Dog, Great Dane and Pug are highly prone to Demodicosis.
Main cause
The main cause of Demodicosis is the mite Demodex Canis, a normal inhabitant of the hair follicle of dogs. When the body’s immune mechanism is unable to control the growing population of mite, then the host suffers from Demodicosis. There is proliferative growth of Demodex mite in the hair follicle and sebaceous glands causing much of the clinical manifestations. Demodicosis occurs in all dogs irrespective of the age. Pups get infected either due to their poorly developed immunity at a younger age or due to depressed immunity as a result of poor nutrition, concurrent infection and stress. On the other hand, adult dogs with a much better immunity than the pups get the disease by virtue of administration of drugs which lower their body’s ability to fight down infections and also while suffering from systemic diseases.
Extent of lesion
Based on the extent of area involved, they may either be a localised lesion or a generalised form localised lesion, with few number of small patches of affected area, tend to resolve spontaneously or sometimes with mild veterinary intervention. Generalised form, where almost the entire body gets involved, demand special veterinary care along with much involvement of time and money on the part of the pet parent. Generalised infection seems to get cured at times but may not be eliminated from its root. Chances are that neglected localised lesions flare up to become generalised ones.
Full treatment
Veterinary attention must be sought soon the pet parent observes any foci of infection or repeated scratching of a particular body region by the animal with foul smell from the body. Pet parents must have full reliance on the clinician. Most treatments fail as pet parent terminates the treatment on visible clinical resolution. It is important to depend on the length of the treatment as clinical resolution occurs 1-6 months sooner than actual parasitological cure.Clinically improved dogs still harbor Demodex mite which might relapse sooner or later. Relapse also occurs during estrus, pregnancy, lactation and systemic diseases. Therefore, rechecking must be done by skin scraping every four weeks to see the response until two consecutive scrapings are negative.
Balanced diet
Meanwhile, as the dog undergoes treatment for Demodicosis, pet parents must make sure that their dogs are provided with a nutritious balanced diet to boost up the recovery and create an environment with minimal stress. Adequate exercise and keeping the dog in a comfortable condition should be available to the dog to ease its recovery. Most dogs perform well when provided with adequate assistance along with proper medication.
(Dr A Sangaran is professor at the Department of Veterinary Parasitology, Madras Veterinary College and a member representing India at Tropical Council for Companion Animal Parasites (TroCCAP) in Melbourne. Dr Neelakshi Deka is also from the Department of Veterinary Parasitology, Madras Veterinary College, Tanuvas, Chennai)