Page 1018 - Veterinary Immunology, 10th Edition

VetBooks.ir Treatment of Type I Hypersensitivity

By far the most satisfactory treatment of extrinsic allergic disease is
avoidance of exposure to the allergen. Specific immunotherapy

gives good responses in up to 80% of cases, but secondary
infections such as bacterial or yeast (Malassezia) infections or flea
infestations must also be controlled. Allergen-specific
immunotherapy may also be used. This has the potential to induce
stable, long-term remissions but is not a substitute for avoidance.

Topical therapy such as bathing with mild shampoos helps
considerably. Diets enriched in the omega-3 fatty acids
eicosapentaenoic acid and docosahexaenoic acid may be beneficial

when fed to dogs with chronic allergic dermatitis. Omega-3 (fish)
oil or omega-6 (evening primrose) oil probably promote the
synthesis of antiinflammatory eicosanoids.
The principal indications for drug therapy include short-term
temporary relief either while waiting to begin immunotherapy or

while waiting for it to take effect. Drugs may also be useful for
relief of transient recurrences or in animals in which
immunotherapy is not possible. Many different drugs are available

to treat type I hypersensitivity, although veterinarians tend to
employ only a few of these.
Topical or oral corticosteroids are most commonly used to reduce
the irritation and inflammation associated with the acute allergic
response. These drugs can suppress all aspects of inflammation by

inhibiting NF-κB and blocking the production of inflammatory
mediators (Chapter 41). Corticosteroids have a considerable
palliative effect on chronic type I hypersensitivities but can have

serious side effects. They are immunosuppressive and can increase
susceptibility to infection. The effective dose of prednisolone may
be significantly reduced by the use of an oral essential fatty acid
supplement. Other immunosuppressants such as the calcineurin
inhibitors, cyclosporine, and tacrolimus may have similar benefits.

The β-stimulants include epinephrine, isoprenaline, and
salbutamol; α-antagonists include methoxamine and
phenylephrine. All have been used extensively in humans and are

available for use in animals. Epinephrine is the most important

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