Truckstop was a 6-8 week old black Labrador Retriever presented by a concerned neighbor to the veterinary dermatologist for evaluation of a severe itch and generalized crusting dermatitis of unknown duration.
Past medical history was not available. The skin lesions involved the entire face, neck, limbs, elbows, hocks, abdomen, chest, and portions of the trunk. At these sites, lesions consisted of papules and crusts with profound hair loss. Secondary lesions included thickening of the skin, darkening of the skin and widespread excoriations due to relentless scratching and self-trauma.
Causes
A list of the causes for all lesions and itch in a young puppy was generated. The primary considerations were parasites that cause itch and/or hair loss in young dogs. Basic in-hospital diagnostic tests were performed by the veterinary dermatologist and included skin surface cytology, deep skin scrapings, and superficial skin scrapings. A fecal examination was also performed.
Cytology confirmed surface pyoderma and superficial bacterial folliculitis (bacterial skin infections). Demodex mites were recovered from deep skin scrapings, and the diagnosis of generalized juvenile-onset demodecosis was made. Sarcoptes mites were recovered from superficial skin scrapings, and the diagnosis of sarcoptic mange was made. Roundworms and demodex mites were recovered from the fecal examination.
Treatment
The initial treatment plan prescribed was antibiotics and benzoyl peroxide shampoo therapy for the skin infection and Selamectin (Revolution®, Pfizer Animal Health) for the treatment of the sarcoptic mange. Appropriate deworming medication was prescribed by the primary care veterinarian. The puppy was also placed upon a good plane of nutrition.
We elected not to institute treatment of the demodex mites at the initial visit. In cases such as this, treatment of the major problems may reduce the burden on the pet’s young immune system and, in time, permit the immune system to “recover” and eliminate the mites without a need for medication. After four weeks of this initial treatment, the puppy was thriving.
The itch, sarcoptic mange and bacterial skin infection were resolved and there was considerable regrowth of hair. Revolution® was discontinued, the course of antibiotics was completed, and the frequency of bathing was decreased to once every 14 days. Also at this reevaluation, deep skin scrapings were performed on sites of persistent hair loss. Demodex mites were recovered in high numbers from five locations.
While one could have elected to continue monitoring for the resolution of these mites over time, the decision to treat this case of generalized juvenile-onset demodecosis was made. There are several effective treatments for juvenile-onset generalized demodecosis. For this patient, extra-label usage of ivermectin was prescribed at dosages reported to be effective for demodex. Ivermectin was administered orally once-daily until the veterinary dermatologist confirmed that there had been two visits at which no mites were recovered.
After this confirmation, the ivermectin was continued for two additional weeks and discontinued. For this pet, all medications were completed 12 weeks after the initial presentation to a veterinary dermatologist.
This case demonstrates how the severity of lesions does not dictate a case outcome if the cause of the lesions and symptoms are identified and treated. In our assessment, the majority of Truckstop’s lesions and all of the itch were secondary to the sarcoptic mange and bacterial skin infection. Once these two problems were treated successfully, itch resolved and the skin character gradually returned to normal. We were then able to more specifically address the demodex.
Truckstop made a full recovery and went on to live a very happy life in a loving home.
