Originally appeared as Ask the Vet by Dr. Shawn Ashley in Pug Talk Magazine (May/ June 1991 & March laprit 1993)
Demodex is a normal mite found on the skin of many animal species. Dernadectic mites are host specific and will not cross from species to species. Demodicosis is an inflammatory skin disease often referred to as the red mange. It is believed to be associated with a host immunodeficiency and is diagnosed by the presence of larger than normal numbers of live mites in a skin scraping specimen.
Transmission is generally direct skin to skin contact usually from the bitch to nursing neonates during the first 2-3 days of life. Pattern of hair loss usually begins on the muzzle, head, and the front legs. Truncal areas may have local circular areas of alopecia. Generalized demodicosis often starts as local lesions; if the animal's immune system does not cause spontaneous regression the disease can affect the whole body without proper treatment.
Demodex has also been documented in certain cases of chronic ear (otitis external and foot (pododermatitis) infections. Chronic demodex comprises skin integrity rendering it to secondary bacterial infections.
Certain breeds, Pugs included, seem predisposed to generalized demodicosis. It is recommended that carrier bitches and siblings be eliminated from breeding programs. It has been suggested to watch puppies with localized lesions. If they do not recover spontaneously or with minimal topical therapy, treatment should be implemented and the affected pup spayed or neutered. A cesarean section and handraising of litters will cut down exposure but does not improve the inherited immune component.
Treatment is usually very effective with localized lesions healing on their own with topical rotenone or benzyl benzoate lotions. On the other hand, generalized demodicosis can be very serious, resistant, sometimes life- threatening disease. Amitraz (Mitaban) dip has proven to be quite successful in treating these cases. until two negative skin scrapings fourteen days apart have been obtained. It is imperative to soak the whole animal when dipping, including the interdigital areas of the feet.
Demodectic pododermatitis can become a severe amitraz resistant problem. It can be present with or without generalized manifestations. The feet become very swollen and painful. Clinical trials are now being studied in using milbemycin (the active ingredient in the new monthly heartworm preventative, Interceptor) as an alternative treatment in these resistant cases.
NASAL FOLD DERMATITIS
Due to the conformation of the brachycephalic breeds they are prone to nasal fold infections. The deeper the folds the harder to clean and the greater the likelihood of a moist dermatitis to occur. If the occurrence of these infections is not controlled, eye infections may ensue. The eye conditions arising rom nasa fold dermatitis should be differentiated from the severe corneal ulcers seen due to extensive nasal folds that actually rub against the eyes - -medical management alone will not cure this matter; surgical removal of the fold is the treatment of choice. Surgery may also be recommended in those cases where chronic nasal fold infections (or the dog) are becoming refractory to medical therapy.
The best medicine with regards to nasal fold skin infections is preventive; keep the areas clean and dry using skin cleansers (Chlorohexiderm skin flushes, CVMD skin cleanser) and cotton swabs to get into the folds. Medicated, antiseborrheic shampoos may be helpful in managing related skin infections, as well. Be sure to use ophthalmic ointments in eyes prior to cleaning around the face. Also, cleaning of nasal folds, ears, teeth and nail trimming should start as a puppy or it may never be allowed to happen!