In Nepal, especially in Kathmandu, the dog owner complain about numerous skin problem seen in their dog and mange affecting their dogs tops that list. It is the most common skin problem of dogs in the cities.
What is mange?
Mange is an inflammatory skin disease in dog caused by mites. The term mange is derived from French word mangeue which mean to eat or itch. Mange is caused by different types of mites which affect many kind of animals including we human species.
There are mainly two types of mange
In this blog, we are going to explain the Demodectic mites. I will write about Sarcoptic in my next blog. It is necessary in this aspect that the causative agent, symptom and treatment pattern of both are quite different.
Demodectic mange, also known as red mange or demodex, is the most common form of mange found in dog. It is caused by Demodex Canis, a parasitic mite that lives in hair follicle of dog. This mite is shaped like cigar with eight leg and can be easily detected under microscope. It is a natural inhabitant of hair follicle of most of the animal. Most dog acquire Demodectic mange mites early in life from their mother. However it causes no significant problem .In most cases, the symptom of disease doesn’t develop due to the healthy immune system of dog. In other word it is kept in dormant stage. However if the immunity is compromised or weak, then the numbers of mites flare up and the disease is developed. So healthy immune system is necessary to ward off these conditions. It is seen in practice that puppies and older( > 8) years dog have weaker immune system so they have more chance of showing the sign of these mite infestation. The condition developed by these mite is not proved to be contagious to human or other animal till date. So there is no risk of transmission between pets.
What are the symptoms of Demodectic mange in dogs?
Demodectic mange can take three forms in dogs:
Scaly bald patches can form on the dog’s face. It’s common among puppies and in dogs up to one year of age. Consult your vet who will decide if treatment is necessary. It begins as thinning of hair around eyelid, the lips and corner of mouth and front leg, giving a moth-eaten appearance. It progress to patches of hair loss about one inch in diameter (which may be confused with ringworm)If more than five patches are present, the disease could be progressing to generalized form. After one or two month the hair begins to grow back. Generally most of the cases are healed in three month..
This starts out as a localized case but instead of improving it get worse and turns to generalized form and it may be life threatening .This is when more parts of a dog’s body are affected by the patchy, infected skin. Numerous patches appears on head, legs and trunk. The patches coalesce to form a large area of hair loss. Hair follicles become plugged with mites and debris. Secondary infections can make the condition very itchy and your dog may smell. Skin breaks down to form sores, crusts and draining sinus tract— presenting a severe and disabling condition.. When generalized Demodectic mange occurs in older dogs, it is an indication of a potential underlying problem affecting immunity.
This is when the condition just affects the paws but it can be hard to treat and diagnose. Bacterial infections usually develop with this condition and the infection can often run deep through the tissue.
Surprisingly, a dog with Demodectic mange usually does not itch severely, even though it loses hair in patches.
How is Demodectic mange diagnosed?
Your veterinarian will take deep skin scrapings and examine them under the microscope to diagnose this disease. The finding of larger than normal numbers of Demodex mites in skin scrapings confirms the diagnosis.
The localized form is usually treated with topical medication. Many cures attributed to drugs probably are spontaneous recoveries. Watch closely to be sure that localized form is not progressing to generalized form. The generalized form requires more aggressive treatment using special shampoos and dips, along with oral medication. Shampooing with special cleansing shampoos containing benzoyl peroxide helps to flush out and open the hair follicles prior to dipping Clip away all infected hair to facilitate topical therapy. In some cases, secondary skin infections complicate the condition, requiring antibiotic therapy. Because dogs with skin infections often have very red, inflamed skin, Demodectic mange is often called ‘red mange Culture from infected skin sores will determine the most effective antibiotic. Treatment is prolonged and the response is slow requiring frequent change in medication which could be frustrating to owner. Cure is not always possible. However good results have been reported using amitraz dip. But it is a potent insecticide and has some serious side effect if not used properly.
Corticosteroid for e.g. prednisolone is contraindicated because it depress dog’s immunity to the mite, making the condition worse.
Generalized Demodectic mange and pododermatitis should be treated under veterinary supervision..
Because the immune system does not mature until 12 to 18 months of age, a dog with Demodectic mange may have relapses until that age. In addition, dogs with suppressed immune systems may be susceptible to relapse. It is important to treat as soon as a relapse occurs to minimize the possibility of developing uncontrollable problems. Relapses are usually recognized 3-6 months after treatment is discontinued.
Can Demodectic mange be prevented?
Keeping your dog in optimum health will reduce the likelihood of your dog developing Demodectic mange as it will give his immune system the best chance of suppressing the parasites responsible. Stress can affect immunity, as can hormonal changes, so neutering will also help. Beside this keep your dog’s worming and flea/ticks treatments up to date.
Written by Dr Pratik Man Pradhan B.V.Sc &A.H
Chief Veterinarian Mount Everest Kennel Club