Susan L. Clubb, DVM, Dipl ABVP (Avian)
Affiliation: From the Rainforest Clinic for Birds and Exotics, 3319 East Road, Loxahatchee, FL 33470, USA.
Abstract: Feather damaging behavior is often associated with inflammatory skin disease as determined by paired skin/feather biopsies in affected birds. This inflammatory skin disease, evidenced by perivascular inflammation, is consistent with atopic or allergic dermatitis as seen in mammals. For clinical management of these cases, the practitioner should use a combination of therapeutic modalities including antihistamines, hypoallergenic diets, nutritional supplements with anti-inflammatory or antioxidant properties, and avoidance of allergens if offending allergens can be identified. No single therapeutic program is effective for all birds. The therapeutic program must be long term and must be tailored to the needs of the owner and the patient. This is an anecdotal report of clinical observations.
Inflammatory skin disease (ISD) in parrots can be a reflection of an underlying systemic inflammatory disease, and is associated with feather damaging behavior (FDB).1-3 ISD is mostly likely analogous to hypersensitivity or allergic dermatitis in mammals. FDB associated with ISD can begin in birds less that 1 year of age, or may take years to develop. ISD, like hypersensitivity disorders in humans or other animals, can be seasonal but is often a chronic, on-going problem. It cannot be cured; it must be managed possibly for the rest of the bird’s life.
The incidence of inflammatory skin disease varies by species; however, in a compilation of 412 cases by Garner, an overall prevalence of diagnosis of ISD was 51%.1,2,4
The predominant clinical signs of ISD are pruritis and plucking or damaging the feathers. Some birds also have erythema or dry, flaky skin. The skin often has insufficient subcutaneous fatty tissue, giving it a reddish color from muscle layers below. In severe cases, birds may mutilate the skin as well. A bird with inflammatory skin disease is often scratching while in the exam room. Clients may describe the bird as having severe episodes of obvious discomfort, often jumping, twitching, or vocalizing as if irritated.
Onset of ISD may be very sudden, possibly in response to the bird coming into contact with increasing or varying levels of antigen. Onset may also coincide with molting and may indicate follicular inflammation associated with the emergence of feathers. Birds may discontinue the behavior when moved to a new location, which may logically remove it from the offending allergens. Owners often report that they brought a FDB bird into their home and the behavior stopped. They may associate this change with improvements in diet or providing more toys while the response may actually be due to removal from the source of allergens. This response may be temporary as the bird becomes sensitized to new allergens in the new environment.
ISD cannot be definitively diagnosed by physical exam. Diagnosis is based on paired skin biopsy as previously described.1,5,6 In this procedure, the bird is anesthetized and 2 growing feathers with a small section of skin surrounding each are biopsied for histopathologic examination. One sample is taken from an area of skin where the bird is plucking, and another sample is taken from an area of skin where the bird is not plucking or cannot reach (usually the head or neck). Actively growing feathers are preferred because they are more reflective of current conditions in the follicle and helpful in diagnosis of other follicular abnormalities.
Inflammatory changes, typically perivascular inflammation, is expected in affected areas and can be simply associated with trauma of the scratching and plucking. If these inflammatory changes (lymphoplasmacytic perivasculitis) are noted in unaffected areas as well, this suggests a systemic inflammatory process. If no abnormalities are found in either section, or inflammation exists only in the affected areas, the FDB is most likely associated with psychogenic disorders by process of elimination.
Macaws, Amazon parrots, conures, lories, and Eclectus parrots have a high incidence of ISD.4 ISD is not so common in cockatoos and African grey parrots, which seem to have a higher incidence of psychogenic FDB. Other disorders may also be diagnosed by paired skin biopsy, including bacterial folliculitis or dermatitis, fungal dermatitis, follicular or feather dysplasia that may be associated with viral infections, hyperkeratosis that may be nutritional in origin, and even dermal hemosiderosis. If characteristic feather dysplasia is present, testing for psittacine circovirus is indicated
Bacterial and fungal secondary infections may actually be triggering effects as in dogs that have allergic dermatitis. Treatment of these secondary infections may enhance control efforts.7 Unfortunately, at this time, allergy testing by skin tests or blood tests are not practical or available for birds.8
Therapy for Inflammatory Skin Disease
Therapy for ISD is based upon reduction or control of the allergic response with antihistamines, provision of a hypoallergenic diet if possible, elimination of allergens as much as possible, and provision of optimum levels of specific nutrients that help to control inflammation, and enhance metabolism.7,9 I have found supplementation and balancing omega 3 and omega 6 fatty acids, which is often used in other species to reduce inflammation, is also clinically beneficial in birds. My goal in fatty acid supplementation is 50-250 mg/kg body weight of omega 3 fatty acids with an omega 3:omega 6 ratio of 1:2-1:6. When supplementing extruded diets I use a balance supplement of salmon oil and flax seed oil (high in omega 3 fatty acids) and safflower seed oil (high in omega 6 fatty acids). If the bird is eating a primarily seed diet, I supplement only with salmon oil and flax seed oil.
Due to concerns for adverse side effects, I have not initiated therapy with corticosteroids. Ideally in hypersensitive individuals, known allergens should be avoided as much as possible. Because we cannot test to determine which allergens should be avoided, we must try to simplify the diet and reduce exposure to items known to be allergenic in mammals.
Food allergies or sensitivity can be difficult to diagnose even in humans and dogs. The standard approach when dogs are suspected of having food allergies is to simplify the diet as much as possible, excluding foods, especially proteins, that are suspected to be allergenic. The author has found that feeding an exclusion diet may consist of a simplified balanced formulated diet to be clinically beneficial. I have used a hypoallergenic extruded diet based on rice and with high levels of flax seed and found it successful in some birds, but acceptance is often challenging (Kaytee Products, HA Prescription Diet, Chilton, WI, USA). Manufacturers of hypoallergenic diets for dogs generally recommend that the exclusion diet be provided as the sole diet for at least 8 weeks to assess success. This can be challenging for many bird owners. Preferably, birds should be fed at the owner’s mealtime to reduce begging for human foods. Supplemental foods and treats should be provided from the list below.
Suggested supplemental foods
Birds and owners love dietary variety and sharing at mealtime. In order to enhance compliance, a list of foods that have relatively low antigenicity and do not contribute to skin inflammation was developed for owners to share with their birds. This was based on avian as well as human literature.10,11 Supplemental foods should be chosen from the following list. If the bird is begging for table foods at dinnertime, offer these foods. They can also be used for treats and to enrich the diet.
- Cooked or canned salmon
- Cooked chicken
- Spinach or kale
- Green peppers
- Green beans
- Cooked eggs
- Shelled Brazil nuts (raw unsalted)
- Spirulina-(if marine algae)
- Olive oil
- Pinto beans
- Soybeans (roasted)
- Cottage cheese
- Sunflower seeds (shelled-limited quantity)
- Black beans
In the initial exclusion phase of dietary restrictions, additional foods should not be given. After the first 2 months, new foods should be added 1 item a week in order to detect specific items that the bird may be sensitive to.
Birds affected with ISD often benefit from treatment with antihistamines. But antihistamines don’t seem to work for all species or all individual birds. It is possible that in some birds, ISD may be mediated by some pathway other than histamine. Macaws seem to benefit most from antihistamine therapy.
I often observe seasonal allergies in birds with ISD, especially in macaws. This is a reflection of systemic allergic disorders. Seasonal allergies may coincide with seasonal peaks in pollens, molds, or other allergens.
If antihistamines are used, I usually recommend chlorpheneramine maleate without other ingredients such as decongestants (chlorpheniramine maleate, 4 mg; Contact Pharmaceutical Corp, Hauppauge, NY, USA) This drug is difficult to find over the counter. It is conveniently administered in the drinking water at the rate of 1 tablet in 1 cup (8 oz, ~236 ml) of bottled water. In my experience, water dosage is beneficial because the bird doses itself repeatedly during the day. Some individuals respond well to loratidine syrup (Children’s Claritin Syrup, 5 mg/ 5 ml; Schering Plough, Kenilworth, NJ, USA), which in the 24-hour formulation can be given orally once daily at the dosage of 0.5 ml/100 g body weight. Dosage may need to be titrated to effect for individual birds. Overdosage can result in extreme lethargy or hyperactivity and agitation.
Hydroxyzine hydrochloride solution (10 mg/5 ml; Morton Grove Pharmaceuticals, Inc, Morton Grove, IL, USA) is another alternative for antihistamine therapy and, as with chlorpheneramine, it also has a mild sedative effect. This drug can also be administered directly orally (2 mg/kg, q8h), but such frequent oral dosage is unacceptable to most clients. I use 5 mg/kg q12h or 10 mg/kg once daily added to soft food for more continuous dosing. Some clients can identify times of the day when plucking is more intense. Routine dosing of hydroxizine at this time, or on a symptomatic basis, can be a useful management tool.
Many tricyclic antidepressants such as haloperidol (Haldol, OrthoMcNeil, Raritan, NJ, USA) also exhibit potent antihistaminic effect and can be especially beneficial if the bird exhibits psychogenic behaviors and also has ISD.
Bathing, even with only fresh water, helps to reduce skin inflammation. I recommend bathing the bird at least twice weekly. Soak the bird with tepid, fresh water. Ideally, the bird should be allowed to dry in sunlight. A solution of aloe vera may be sprayed on the feathers and skin once or twice weekly, especially if the skin is very irritated (Aloe Vera Detoxifying Formula, Naturade, Inc, 14370 Myford Road, Irvine, CA, USA). One oz contains 29.6 ml of aloe vera gel, 600 mg aloe vera pulp. Aloe vera gel or solution is mixed 2 tsp in 8 oz water to spray on skin. To prevent build-up of aloe vera on feathers, intermittent fresh water baths are recommended. Aloe vera may also be administered in drinking water at the rate of ¼ tsp in 1 cup water.
It is important to avoid getting oil supplements on the bird’s feathers because they can cause matting and discoloration. If feathers become soiled with oil, they can serve as a substrate for saprophytic fungi to grow on the feathers.3 If this occurs, a weekly misting of chlorhexadine solution (Nolvasan, Wyeth Laboratories, Philadelphia, PA, USA) diluted 1:10 in water can prevent the spread of the saprophytic fungi from infected feathers to new ones. Bathing with fresh water between chlorhexadine mistings will reduce buildup on the feathers. Oil from the owner’s hands and face, or oils from foods, can also accumulate on feathers and be a substrate for feather fungus.
Improvement with therapy using exclusion diet, antihistamines, and antioxidants will be gradual. This is especially true if feathers are broken, chewed of otherwise damaged, rather than being plucked out in their entirety, because the bird must molt in order to replace the old feathers with new ones. Therapy must be continued for at least 3-4 months prior to assessing effectiveness.
Taking photos of the bird is the best way to monitor its progress. Preferably these photos should be taken in the same place with the same lighting each time for ease of comparison. Monthly digital photos are ideal.
When managing chronic problems, it is very important to give any therapy adequate time before stopping or changing treatment. Long-term therapy is challenging, so every attempt should be made to make it easy for the owner and palatable to the bird. As the inflammation resolves, the bird will feel better and its attitude and personality will usually improve as well.
1. Clubb SL, Garner MM, Cray C. Detection of inflammatory skin disease in psittacine birds using paired skin biopsies. Proc Annu Conf Assoc Avian Vet. 2001.
2. Clubb SL, Garner MM, Cray C, et al. Diagnostic assessment of feather damaging behavior in African grey parrots (Psittacus erithacus). Proc Annu Conf Assoc Avian Vet. 2004; 313-320.
3. Clubb SL, Herron A. Feather discoloration associated with saprophytic fungal growth. Proc Annu Conf Assoc Avian Vet. 1998.
4. Garner MM. Techniques and trends in the characterization of inflammatory skin disease in feather picking birds. Proc Annu Conf Assoc Avian Vet. 2006. In press.
5. Garner MM. Avian noninfectious skin disorders. Proc Annu Conf Assoc Avian Vet. 2003;21-24.
6. Schmidt R. Use of biopsies in the differential diagnosis of feather picking and avian skin disease. Proc Annu Conf Assoc Avian Vet. 1993;113-118.
7. Hillier A. Practical symptomatic therapy for allergic dermatitis. Western Vet Conf. 2004.
8. Colombini S, Foil C, Hosgood G, et al. Intradermal skin testing in the avian patient. Proc Annu Conf Assoc Avian Vet. 1999;129-131.
9. Welle KR. Clinical approach to feather picking, Proc Annu Conf Assoc Avian Vet. 1999;119-124.
10. Surai PF. Natural Antioxidants in Avian Nutrition and Reproduction. Bath, England: Nottingham University Press; 2003.
11. Perricone N. A Doctor’s 28-day Program for Total Body and Face Rejuvenation. New York, NY: Time Warrner Book Group; 2003.