Skin Allergies

Your bird has a sudden change in behavior. She is using her claws to scratch her head more than usual, she is rubbing her face on her perches and she has begun plucking feathers from under her wings. She appears itchy to you (the technical term is pruritis). Could she have a skin allergy?

Allergies do occur in birds but are considered somewhat of an enigma medically. What exactly is an allergy? Scientifically-speaking, an allergy is a body's abnormal reactivity to a substance called an antigen that evokes an exaggerated or abnormal immune response (such as sneezing, wheezing, itching or a rash). Antigens are normally proteins. So, put in basic terms an allergy is a body's over-reaction to things called allergens. Exposure can occur from touching the allergen, inhaling it, ingesting it or if it is injected into a body.

Skin allergies in birds may manifest by swelling in the skin, oozing from the skin itself or from inflamed feather follicles, itchiness, redness or feather loss. In dogs, some types of inhalation allergies present as itchy skin of the ears and feet. This occurs from a histamine release from certain white blood cells in the ears and feet. Histamine causes a reaction resulting in redness, itching and swelling. For example, when bitten by a mosquito, the localized reaction in the skin is caused by a histamine release in response to the saliva in the bite. Not surprisingly, the saliva of a mosquito contains proteins that cause the localized reaction.

In humans and dogs, it is possible to perform certain skin tests in order to diagnose which allergens are causing the reaction in the patient. By injecting minute quantities of diluted known allergens into the skin and then grading the reaction, it is possible to identify allergens. In some cases, blood tests can be performed to assess possible allergens, as well. Unfortunately these two types of tests are not available for use in our avian patients. With birds suspected of having allergy problems, it is possible to evaluate the White Blood Cell count (WBC) and differential to look for the one type of white blood cell, called the eosinophil, that can elevate due to allergic problems or also from parasitic infestations. A biopsy of the skin, including a feather follicle may help in diagnosing allergic skin disease in birds.

If a bird has a skin problem that is suspected of having an allergic cause, I will need to work with the owner to develop a detailed history to look for trends for clinical signs in an attempt to look for possible exposures. For example, it has been observed that some Amazon parrots housed outdoors near some species of oak tree found in Florida will develop swelling and redness around the eyes, conjunctivitis and discharge from the eyes. Some affected birds may also develop sneezing, rhinitis and swelling of the cere. The allergen is suspected to be related to the pollen that is produced when these trees are blooming in the spring. This fine yellow, highly irritating pollen wreaks havoc in humans suffering from allergies and is probably affecting some birds, as well.

Some Amazon parrots, most notably Double Yellow Headed Amazons and Yellow Naped Amazons, seem to suffer from a suspected seasonal allergy that causes the skin and scales of the feet and legs to become swollen, cracked and peeling. This is a very painful condition for a bird, especially since the skin of the feet cannot easily swell. There is still much to learn about this condition and why it appears to occur most often cyclically.

There is another condition that occurs in some species of birds, often lovebirds and African grey parrots that affects the skin in the area of the wing web and under the wings. The skin may become thickened, red and may ooze or actually crack and bleed. This is also a very painful condition requiring veterinary care. Biopsy of affected skin may show cells consistent with an allergic problem, but many are also infected secondarily with bacteria or fungi. In some cases, a virus is a suspected cause, but many show a mixed inflammatory reaction, with the suspicion that allergies are involved.

There is a very interesting condition that occurs in cockatiels and occasionally in other species in the parrot family. Many affected birds are very itchy, and may actually cry out when pulling out their own feathers. With this condition, feathers are most often plucked out under the wings, on the chest and in the inguinal area (the inside of the thighs). It is thought that birds harboring intestinal protozoa (usually Giardia sp. but also perhaps Hexamita) have an allergic reaction to the protozoa in their intestinal tract, resulting in the itching and feather plucking problems. Another school of thought is that the protozoa compete for nutrients in the intestines, causing a nutritional imbalance, resulting in skin problems.

Birds may become the host to several different types of biting lice or mites. One offender, the Dermanyssus mite, only feeds on the bird at night, and during the day, it crawls off to sleep in cracks and crevasses around the cage. For this reason, this mite may be difficult to diagnose if the bird is examined during the daytime. The bite from these mites can cause a localized allergic reaction in the skin, and often a bird suffering from mite bites will have ragged, unkempt appearing feathers and red, itchy skin. They may also develop secondary bacterial or fungal skin infections.

Another type of skin condition occurs that is technically not an allergy, and is called contact dermatitis. This happens when a bird comes in contact with an irritant. This usually occurs on the bottoms of the feet. Smokers who don't wash their hands before handling their bird may transfer tar, nicotine and other irritants from cigarettes to bird's feet. This can cause a bird to develop swelling, irritation, cracking, itching or ulceration of the feet. This is a very painful condition requiring veterinary care.

Contact dermatitis can also occur if a bird is sensitive to a particular laundry detergent or fabric softener, for example. Hand lotion, cologne or other topically applied preparations can also cause a bird to develop skin problems, especially on the bottoms of the feet.

A thorough evaluation of the bird's diet, environment and activities should be performed after a complete history is taken. Any bird with a skin or feather problem should undergo a complete physical examination, including close inspection of the uropygial gland, ensuring that the wick feather is present and that, if rolled through the fingers, it leaves a greasy secretion on the fingers. Amazons and the purple macaws are the only parrots that don't have an uropygial gland. A complete blood count and plasma chemistry panel may prove helpful in assessing a bird with suspected allergic dermatitis problems. Skin conditions are often difficult to diagnose without a skin biopsy.

One way to possibly diagnose an allergic problem is to avoid the offending substance and see if the bird's condition improves. Avoidance of allergens is the best way to go, if allergens are identified. If protozoa are suspected as causing pruritis, skin and feather problems, then treatment with ronidazole is an excellent way to attempt eradication. In my experience, metronidazole, a commonly used antiprotozoal, is not as efficacious in our avian friends as ronidazole proves to be. Always use your avian veterinarian for medical problems and do not attempt treatment without your vet's expertise.

Antihistamines, either administered orally or topically, may provide some degree of relief in cases of allergic dermatitis. There are several different types of antihistamines, both over-the-counter and by prescription that may be prescribed by your avian vet, to see which, if any, seems to help in each case. Steroids, sometimes used in dogs and cats to help in cases of allergic dermatitis, should never be used in birds, with very few exceptions. Some topical lotions and creams often prescribed for dogs and cats diagnosed with allergic dermatitis contain a mixture of antibiotics and steroids, and while safe and efficacious in dogs and cats, are also contraindicated in birds.

In some cases, the use of a non-steroidal anti-inflammatory medication will help the bird suffering from feather-follicle inflammation and skin irritation. This should only be administered if prescribed by your avian veterinarian.

Skin problems in birds can be frustrating and most often there will not be a quick fix. Work with your avian veterinarian and follow his or her instructions and prescribed treatments, and over time, hopefully your bird will once again be healthy and happy.

Cadeusus
Copyright 2013 Margaret A. Wissman, D.V.M., D.A.B.V.P.
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