Warmer days tempt us to spend more time outdoors, frequently in the company of our dogs, who enjoy running and rolling in the grass and sniffing the flowers. The downside of this wonderful time of year is the potential for all of those lovely growing things to provoke allergic reactions.
Like us, dogs develop environmental allergies. Is this a condition we just have to contend with year after year, or is there something more we can do to help our pups?
In an allergic condition, the immune system overreacts to a perceived invader. Normally, a dog’s immune system can distinguish between a threat and a nonthreat. Pollen and other mild allergens are essentially non-threats and really shouldn’t cause an immune reaction, but in some dogs, they do, for reasons not yet fully understood.
Allergy symptoms come in many forms, from increased sneezing and running eyes to itchy skin and rashes. Humans reach for tissues, but dogs don’t have this option, so they rub their face on the floor or ground and paw at their eyes. In cases of atopic dermatitis, a skin disorder, increased ear-scratching and foot-licking are common; all of this scratching and licking can result in secondary bacterial skin infections, which further complicate the overall problem.
Veterinarians traditionally rely on either antihistamines or corticosteroids to ease the symptoms, and prescribe antibiotics in cases of infection.
Antihistamines, which are not as effective in dogs as they are in people, commonly have side effects—drowsiness or, occasionally, hyperactivity. Steroids are often used as well; many dogs are put on a low-dose regimen to control clinical signs associated with allergies. Other treatment options include medications such as cyclosporine and hypersensitization injections. Regardless of the strategy, we need to consider whether we are correcting the problem or just covering it up. In most cases, we are simply managing the clinical signs; once medications are discontinued, the problem resurfaces. Antihistamines work directly against a type of immune cell called a mast cell. Mast cells contain histamine granules that, when released, trigger symptoms such as itching and nasal discharge. Steroids act directly on the immune response; their mission is to suppress the immune system or put it into sleep mode so that it doesn’t react to nonthreat invaders (for example, pollen). The problem with steroids is that they have many side effects, ranging from increased appetite and weight gain to greater susceptibility to infection and even the possibility of organ damage when used long-term.
Tissue in the intestinal tract is thought to have an important immune-system function. Thus, a faulty immune response may be linked to poor gastrointestinal (GI) health, or what has been termed “leaky gut syndrome”; I tend to approach my allergy patients from this perspective. The GI tract normally maintains a distinct barrier between the bloodstream and what is ingested. Poor GI health, thought to be the result of chronic inf lammation, compromises that barrier and allows many different antigens, bacteria and proteins to cross it. This elicits an ongoing inflammatory and immune response and precipitates allergies as well as a host of other health conditions.
Repairing this gut barrier takes time and, in most cases, requires a total change of diet as well as the use of supplements. I ask owners to switch to home-cooked diets that incorporate a variety of protein sources as well as fruits, vegetables and some starches. Many commercial dog foods are full of preservatives, dyes and other additives that contribute to the problem, but a home-prepared diet ensures that the dog is getting only what is needed, and also aids in the delivery of vital nutrients.