By Margaret A. Wissman, DVM
Excerpt from BIRD TALK Magazine, May 2011 issue, with permission from its publisher, BowTie Magazines, a division of BowTie Inc. To purchase digital back issues of BIRD TALK Magazine, click here.
Allergies are somewhat of an enigma in birds. If you look up allergy in most avian textbooks, it skips from alkaline to alopecia, no mention of allergy in sight! What is an allergy?
Technically speaking an allergy is a body’s abnormal reactivity to an antigen (a substance foreign to the body, usually a protein) that evokes an immune response. An allergy is also considered to be an exaggerated or pathological reaction (such as sneezing, wheezing, itching or a rash) to substances that aren’t comparable to the effects on the average individual.
Basically, this means that an allergy is the body’s overreaction to things called allergens. When allergies are being evaluated in humans and some companion animals, it is possible to inject minute amounts of diluted allergens into the skin to test and document the body’s reactions to the injections. In some cases, blood tests can be performed to assess possible allergens, as well. But these two types of tests are not performed in our avian species.
In addition to specialized testing, sometimes the white blood cell (WBC) count and differential are utilized to look for possible allergic reactions. For example, with allergies, often one type of WBC is elevated, called the eosinophil, which can also elevate due to parasitic infestations.
Amazon parrots seem to suffer from a suspected seasonal allergic reaction involving the skin and scales of the feet and legs.
Seasonal allergies occur when a susceptible bird is exposed to allergens from flowering plants or trees. Other types of allergies occur in birds (not seasonal), most often in the respiratory systems of birds from Central or South America that live with or are exposed to the dusty birds with lots of powder down, namely species from Australia, Asia or the Pacific Islands. Food allergies are another group of allergies that aren’t considered seasonal.
When it comes to allergies, the best advice that anyone can receive is to avoid any suspected allergens whenever possible. With each exposure, the body’s immune system may over-react more and more violently. This is called sensitization. Think of a person who is allergic to bee stings. The first exposure may elicit a strong reaction in the body, causing constriction of the airways and swelling. The second sting causes a reaction to occur more quickly, since the body recognizes the allergen, and the swelling and constriction are more serious and can prove life-threatening or fatal without immediate treatment for shock. This is why people known to be allergic to bee stings often carry an emergency treatment pack containing a pre-loaded injection pen, filled with epinephrine (also called adrenaline).
What happens when an anaphylactic allergic reaction occurs? When the body identifies the allergen, the immune system causes the release of histamine from certain cells inside the body. Histamine causes cells to leak fluid, causes itching in some tissues, and it also can cause pain at the initial site. The danger occurs when the body has an anaphylactic reaction to an allergen. When this occurs, the blood vessels dilate and the blood pressure drops, and there is constriction in the airway. This is a life-threatening situation requiring immediate treatment. Fortunately, anaphylaxis is not likely to occur with seasonal allergies.
Preventive Measures For Allergies
If your bird has been diagnosed with seasonal allergies, keep your bird away from any suspected or identified allergens, such as pollen or mold. Keep your bird in a clean environment, and minimize dust and dander as much as possible. An air conditioner will remove some particulates in the air and prevent them from circulating indoors. Use a good-quality air filter with HEPA filtration to filter out additional allergens from the air.
Some bird stewards also utilize a type of box fan with an air conditioner filter that is attached to the back that will also filter out larger particulate matter from the environment. Don’t make one of these box fan filters yourself, as there is a risk of fire from it overheating.
There are other things that you can do to prevent or minimize seasonal allergies in birds. Make sure that your bird receives adequate vitamin A in the diet or as a supplement. Beta-carotene is very safe and nontoxic as a supplement that is converted to active vitamin A in the body, and the excess is excreted unchanged, unlike vitamin A, which is toxic if overdosed. Vitamin A is necessary for the lining of the mouth, GI tract and respiratory tract to function properly. Some supplements provide amino acids and other nutrients that help the body heal and repair. These nutrients can provide immune support.
Keeping your bird healthy and on a balanced diet are very important to keep the immune system functioning optimally. It may seem counterintuitive to support the immune system when that is what is causing the allergic reaction to begin with. But it is also important to keep the immune system functioning so that secondary bacterial or fungal infections don’t cause problems either.
If your bird is suffering from allergies, antihistamines can help prevent the release of histamines from the cells, which cause the clinical signs related to allergies. But don’t administer any antihistamines or other allergy medications unless prescribed by your avian veterinarian. But the best and safest route for a bird with allergies is to try to avoid its exposure to any known or suspected allergens.
When I examine a pet bird with suspected allergies, I work with the owner to develop a detailed history to look for trends for clinical signs in an attempt to identify possible exposures. For example, it has been observed that some Amazon parrots housed outdoors under or in close proximity to some species of oak trees found in Florida can develop a profound periocular redness and swelling, conjunctivitis and ocular discharge.
Some also sneeze, develop rhinitis and swelling of the cere. This suspected allergic reaction usually occurs when the oak trees are in bloom in the spring, producing prodigious amounts of fine yellow, highly irritating pollen, leaving a yellow dusting on cars, windows and the ground.
Some Amazon parrots, particularly double yellow-headed Amazons and yellow-naped Amazons, seem to suffer from a suspected seasonal allergic reaction involving the skin and scales of the feet and legs. Often the skin cracks and peels and becomes very painful for the bird. We still need to learn much about why this occurs in these Amazon parrots and why it appears to occur most often cyclically.