Nothing ruins enjoying the warm weather with your horse quite like the scourge of allergies. Manifestations run the gamut from sneezing and snorting to wheezing, runny eyes and agonizing itching.
from Towcester Vets, UK
Allergies are basically a misdirected and unbalanced immune reaction. When the immune system is exposed to a protein that is not a normal component of the body the usual response is to engage both major arms of the immune system (termed Th1 and Th2) to develop antibodies of the IgG and IgA class. In individuals prone to allergic reactions, IgE antibody is produced and primarily the Th2 type reactions are activated. When the sensitized immune system is next exposed to the same protein (called an allergen), a reaction is triggered which results in release of chemicals like histamine.
Why some horses are prone to allergy is not entirely clear but studies have suggested a strong genetic component. A horse can inherit the predisposition to develop allergies but will not inherit any specific allergy such as to a particular food.
Management of the allergic horse includes minimizing exposure to the trigger as much as possible. Antihistamines may be used to try to prevent the development of new reactions but antihistamines cannot reverse symptoms already present. Corticosteroids are typically prescribed for problems that do not resolve on their own. They are extremely effective but come with side effects such as reduced immunity and metabolic disorder with chronic use or high dosages.
We can help the horse by providing supplements that support a balanced immune response. At the most basic level this includes key antioxidant nutrients of copper, zinc, selenium, vitamin E and omega-3 fatty acids. These are indispensable building blocks for the body’s own antioxidant defenses such as glutathione, EPA, DHA and the superoxide dismutase enzymes.
Vitamin C is a key antioxidant both in its own right and by virtue of its ability to regenerate other antioxidants, like vitamin E, to an active form. It is abundant in fresh grass but activity is lost rapidly in hays. Vitamin C is particularly important in the respiratory system and the eyes. Flavonoids (e.g. quercetin) are plant compounds which work synergistically with vitamin C. MSM also has documented antioxidant activity.
Spirulina is an edible algae which promotes normal balance between the arms of the immune system including supporting the production of IgG and IgA antibodies and healthy levels of histamine.
Finally, several herbs have been found to support a normal balance between the Th1 and Th2 arms of the immune system. These include Astragalus, Siberian Ginseng (Eleutherococcus), Pau D’Arco and Echinacea. Herbals used topically can also provide soothing relief for temporary irritations. Ingredients that excel in this include Aloe Vera, Chamomile, Calendula and Chickweed.
There is no question that allergies can ruin your warm weather fun and torture your horse but there are several nutritional and herbal approaches that can be used to support normal function of the immune system and provide temporary relief for skin involvement.
Eleanor Kellon, VMD