Page 1560 - Clinical Small Animal Internal Medicine

1498 Section 12 Skin and Ear Diseases

noted, the lowest effective dosage and frequency of although these effects appear to be extremely rare with
VetBooks.ir administration should be used as maintenance therapy daily doses of approximately 5 mg/kg/day. The authors
typically recommend a baseline CBC, serum chemistry
(i.e., 0.5–1.0 mg/kg PO q12–24h). These drugs are
expensive and can be difficult to obtain as they are
every six months to yearly to monitor for possible
strictly regulated. Side‐effects include keratoconjuncti- profile, UA, and urine culture. These tests are repeated
vitis sicca (KCS), polyuria and polydipsia due to xerosto- side‐effects.
mia, vomiting, and diarrhea. Laboratory abnormalities In general, response to corticosteroids is poor. They
can include elevation of liver enzymes, hypercholester- can be tried as a last resort if there has been no response
olemia, and hypertriglyceridemia. to other therapeutic options or in cases where those
All retinoids are potent teratogens. Monitoring should options are cost prohibitive. A starting dosage of 1 mg/
include pretreatment measurement of tear production kg/day PO can be used and gradually reduced to the low-
via a Schirmer tear test (STT) and a serum biochemical est dosage and frequency possible. There may be a more
profile at minimum. The authors typically repeat the favorable response in cases where the histopathology
STT and serum chemistry profile in 1–2 months and if findings reveal severe inflammation.
no abnormalities are noted, then once to twice a year. It is important to recognize and treat secondary
The use of tetracycline, doxycycline or minocycline infections, as they can greatly contribute to the patient’s
and niacinamide may be beneficial for the treatment of morbidity. The reader is referred to Chapters 158, 166
SA, especially in short‐coated breeds, given the antiin- and 167 in this section regarding the diagnosis and treat-
flammatory and immunomodulatory actions that can be ment of pyodermas, Malassezia dermatitis, and otitis.
gained when these drugs are utilized in combination. It
generally requires 4–8 weeks before response to this
therapy is seen, although maximal effect may not be Prognosis
appreciated until 3–4 months of therapy are achieved. The prognosis of SA ultimately depends upon the sever-
Side‐effects include vomiting, diarrhea, and decreased ity and chronicity of the disease and the degree and
appetite. Hepatotoxicity is also possible, albeit rare. recurrence of secondary infections. The response to
Tetracycline and niacinamide are dosed at 250 mg for therapy is quite variable from one patient to the next.
dogs <10 kg and 500 mg for dogs >10 kg q8h. When doxy- The disease in the akita can be particularly refractory.
cycline is utilized in place of tetracycline, a dosage of There is no cure for SA and it has a chronic, often
5–10 mg/kg PO q12h is suggested and minocycline can progressive nature which requires lifelong therapy. In
be dosed at 5–12.5 mg/kg PO q12h. The dosage of niaci- and of itself, SA is not a lethal disease but a clinically and
namide remains at 250 mg for dogs <10 kg and 500 mg for cosmetically acceptable response is not always obtained
dogs >10 kg q8h. If a positive response is noted, the and/or may be too expensive or labor intensive for the
lowest effective dosage and frequency of administration owner. For these reasons, euthanasia may ultimately be
should be used as maintenance therapy. chosen.
Ciclosporin is currently the preferred treatment for SA,
especially in severe cases or those that have not responded
acceptably to topical therapy and/or other systemic treat- Eosinophilic Dermatitis
ments. Ciclosporin is a calcineurin inhibitor with a num-
ber of immune‐modulatory functions. Perhaps most Etiology/Pathophysiology
important in the case of SA is its ability to impair T lym-
phocyte function. Ciclosporin has also been shown to Eosinophilic dermatitis, also known as eosinophilic der-
increase the numbers of sebaceous glands. Ciclosporin matitis with edema and eosinophilic cellulitis, is an
(Atopica®, Elanco US, Greenfield, IN, USA) can be admin- uncommon syndrome that has been described in dogs
istered at an initial dosage of 5 mg/kg PO q24h. and has been compared to Wells syndrome in humans.
Ciclosporin has an extended lag time of 4–6 weeks before The disease is presumably multifactorial with myriad
clinical response may be seen. If a positive response is possible triggers including allergic and parasitic diseases,
noted, the lowest effective dosage and frequency of arthropod bites, immune‐mediated disease, stress, and
administration should be used as maintenance therapy. drugs, which culminates in an allergic hypersensitivity
Side‐effects include vomiting, diarrhea, anorexia, gingi- and/or immune‐mediated reaction. In one study, more
val hyperplasia, papillomatosis, secondary infections than 50% of the dogs developed eosinophilic dermatitis
including opportunistic urinary tract infections, following treatment for vomiting and diarrhea. In a more
hirsutism, and involuntary shaking. More serious side‐ recent study that focused solely on the development
effects include nephropathy, hepatopathy, bone marrow of eosinophilic dermatitis in dogs with signs of gastroin-
suppression, and lymphoplasmacytoid dermatosis testinal disease, particularly vomiting, diarrhea and