ACCREDITED CPD
•
•
•
Pulse or weekend treatment is often instituted
after the initial 3 weeks and has been shown to
be very effective. Cephalosporins or amoxicillinclavulanic acid are the most commonly used
antimicrobials for this purpose. A study by Didier
Carlotti has shown that there is no increase in the
development of resistance against cephalosporins when using them for pulse or weekend treatment.
Chronic Malassezia overgrowth often exists concurrently with the bacterial overgrowth. Pulse
therapy with systemic ketoconazole has been
shown to be very effective.
The use of weekly topical antimicrobial shampoo,
e.g. chlorhexidine may in some cases be sufficient to control the overgrowth without necessitating systemic medications.
ACCREDITED CPD
•
target of ASIT is to reduce the amount of immunosuppressive treatment needed. If owners understand what to expect rather than believing that
total control is the target, client compliance and
satisfaction will be much better.
Most cases require lifelong control with immunotherapy, supplemented from time to time with
other medical therapy.
4. Suppression of inflammation:
Antihistamines:
• H1 antihistamines may sometimes give partial relief to the pruritic patient.
• They are usually used in conjunction with prednisolone to help lower the dose of prednisolone
required to control the pruritus and inflammation.
• A selected antihistamine should be administered
for 10 to 15 days before evaluating its effectiveness. If the patient does not respond to one type,
it may be worthwhile to try another.
• In a recent study by Ewert and co-workers, a
combination of hydroxyzine (25 – 100 mg/dog/
day) and chlorpheniramine (1 – 4 mg/kg/day) resulted in an improvement of more than 50% in
lesion scores in 18% of dogs and of the pruritus
score in 30% of the dogs. The investigators judged
the treatment satisfactory in 24% of dogs.
• H2 antihistamines have no action on pruritus.
• Antihistamines commonly used, together with
dosages, are given in the table below.
Figure 7: Small superficial pustules indicating secondary infection on medial thighs of a dog
3. Allergen specific immunotherapy (ASIT):
The cornerstone of therapy of CAD is Immunotherapy
(hyposensitisation or desensitisation). This is the practice of administering gradually increasing quantities of
an allergen extract to an allergic patient to ameliorate
the symptoms associated with subsequent exposure
to the causative allergen. It “down regulates” the allergic response and may raise the allergic threshold. It
alters the balance between TH1 and TH2 cells, which
moderates the sensitivity and tolerance to allergens.
ASIT should be considered for young patients; patients where concurrent treatment with topical shampoos, systemic antibacterial and systemic anti-yeast
medications is not able to control pruritus sufficiently;
cases where corticosteroids have to be used at high
dosages for control of pruritus or where side effects
are unacceptable.
• There is now a choice between injectable and
oral immunotherapy.
• Response to ASIT may take 3 to 10 months.
• The success rate is 65 – 75%.
• It is important to note that only a minority of
cases will be totally controlled by ASIT alone. The
majority of cases will benefit from ASIT but may
require symptomatic treatment, including corticosteroids for some parts of the year.
• It is very important to explain to clients that the