Demodex injai infestation and dorsal greasy skin and hair in eight wirehaired fox terrier dogs

Abstract

Demodex injai mites were detected on trichoscopic examinations and/or deep skin scrapings in eight wirehaired fox terrier dogs with dorsal greasy skin and hair. Histological examination performed in five dogs revealed marked sebaceous gland hyperplasia with lympho-plasmacytic periadnexal dermatitis in all of them. One mite section was observed in one patient. Seven dogs were parasitologically cured after 2 to 7 months of oral ivermectin treatment. Greasy skin and hair resolved in four dogs, was partially reduced in two dogs and persisted in the remaining dog. Skin biopsies were repeated after parasitological cure in two dogs and revealed the persistence of sebaceous gland hyperplasia with mild lympho-plasmacytic periadnexal dermatitis and no parasites. Based on the findings in this case series, the terrier dog breed might be at increased risk for the development of D. injai mite infestation associated with dorsal greasy skin and hair, and microscopically with sebaceous gland hyperplasia. Persistence of sebaceous gland hyperplasia after parasitological cure in some patients suggested that this histological finding may not always be resulting from Demodex infestation. Moreover, low numbers of adult mites and variable clinical responses to acaricidal therapy suggested a contributory rather than a major role of D. injai in this skin condition. Dermatopathological diagnosis of sebaceous gland hyperplasia, particularly in case of dorsal trunk specimens from terrier dog breeds, warrants the search for D. injai mites on trichoscopic examinations and/or deep skin scrapings.

Canine Ichthyosis and Related Disorders of Cornification

“…Idiopathic generalized sebaceous gland hyperplasia has been reported in both Border terriers and wire-haired terriers 17,18 . It is unclear if this disorder is a true cornification defect or a manifestation of another disease process (e.g.…”

“…The terriers present with a greasy haircoat that is most severe on the dorsum. Some dogs, particularly the wire-haired terriers, have been documented with Demodex injai infestation 17 . These long-bodied demodex mites are often found in sebaceous gland ducts in addition to hair follicles.…”

Juvenile‐onset and adult‐onset demodicosis in dogs in the UK: prevalence and breed associations

“…The clinical presentation of demodicosis shows wide variation in the age at onset, the extent and severity of the lesions and the presence of secondary infection, in addition to the mite species involved (Ordeix et al . , Miller et al . ).…”

Clinical aspects of demodecosis in veterinary and human medicine

“…In dogs, the most commonly reported mite species is Demodex canis, which lives in hair follicles, sebaceous glands and sebaceous gland ducts. Furthermore, there is a species of Demodex injai, which also lives in hair follicles and sebaceous glands, but is more often found in adult dogs diagnosed with iatrogenic Cushing's syndrome and hypothyroidism (18,40).…”