Page 1546 - Clinical Small Animal Internal Medicine

1484 Section 12 Skin and Ear Diseases

recognized in companion animals. One case report Treatment of FHV‐1 infection with oral famciclovir is
VetBooks.ir described pruritus in a puppy with a portosystemic shunt effective for cutaneous, ocular, and respiratory symp-
toms. It can be more effective than other therapeutic
whose pruritus resolved upon correction of the vascular
strategies. The drug appears to be well tolerated in cats
abnormality.
but there is some uncertainty about the dose and dura-
tion of treatment, with recent recommendations reflect-
Systemic Infectious Disease Causing ing higher doses than had been used previously. In some
Cutaneous Manifestations cats, the skin lesions can become recurrent or chronic.

Feline Herpesviral Dermatitis Feline Leukemia Virus and Feline
Immunodeficiency Virus Infection
Feline herpesvirus‐1 (FHV‐1) can cause a characteristic
facial dermatitis in cats. The condition is most common Feline leukemia virus (FeLV) usually causes skin lesions
in adult cats, and not all cases exhibit the ocular or res- by its immunosuppressive actions, although it can also
piratory signs typical of this viral infection. There can be induce skin tumors. The cutaneous symptoms are quite
a recent history of an upper respiratory tract infection in nonspecific. Affected cats are susceptible to a number of
the weeks preceding development of the lesions in some secondary infections including recurrent abscesses, pyo-
cats. The lesions consist of inflamed and often ulcerated derma, dermatophytosis, demodicosis, and paronychia.
areas near the nares. They most often affect the nasal Multiple cutaneous horns of the footpads are sometimes
planum, dorsal aspect of the muzzle, and periocular skin seen in cats infected with FeLV. Giant cell dermatosis is a
(Figures 168.4 and 168.5). The lesions do not appear pru- histologically unique and rare manifestation causing
ritic even though eosinophils typically predominate. The pruritus and crusting of the face and often other areas of
clinical appearance and eosinophilic inflammation can skin. Although feline immunodeficiency virus (FIV) is
lead to an inappropriate diagnosis of an eosinophilic more commonly associated with recurrent or chronic
plaque or mosquito bite hypersensitivity, with inappro- oral disease, some cats also exhibit skin infections. The
priate treatment using corticosteroids, which can lead to signs of these two immunosuppressive viral diseases are
marked worsening of the disease. very similar. The diagnosis is made by serologic testing.
The diagnosis of feline herpesviral dermatitis is made
by the fairly striking clinical appearance of the facial Canine Distemper
form, histopathology, and either immunohistochemistry Canine distemper virus infection in dogs can be
or polymerase chain reaction (PCR) testing for FHV‐1 manifested by a combination of respiratory, ocular,
on biopsy samples. Viral inclusion bodies are difficult to gastrointestinal, neurologic, and cutaneous signs that
find on histopathology, so this condition should be con-
sidered in biopsies consistent with eosinophilic plaques
located on the face.

Figure 168.4 Feline herpesviral dermatitis and rhinitis in an adult
cat. Small crusts and a loss of the cobblestone architecture of the Figure 168.5 Feline herpesviral dermatitis in an adult cat. Extensive
nasal planum are seen. unilateral eosinophil‐rich ulceration is present on the face.