Empowered pet caretakers are certainly aware of the incidence of allergies in pets. It is one of the most common problems we find in dogs and cats. Hopefully, by now, we know that allergies are due to damaged gut and immune imbalances and the only way to cure allergies is to restore normal health to these two systems. If you aren’t aware of this underlying cause, then go to my website and check out my blog on seasonal allergies in pets.
As a practicing veterinary clinician for over 35 years, I will be the first to admit that the conventional approach to medicine is often superficial and often fails to look for underlying problems that can connect the dots to diseases. We all know about cause and effect. Most diseases like allergies, are the effect or result of something else. In conventional medicine we often approach diseases as causes of symptoms without being aware that they themselves are the effects of underlying imbalances.
There are often times when allergies can play the role of cause and have effects for other parts of the body. The wise veterinarian will understand this role of the allergy and work to resolve the cause and not just the effects. We consider these secondary problems that can actually cause other problems, we call tertiary complications. In this blog, I will cover some common clinical problems that have been directly linked to allergies.
Allergy presentations differ a bit in dogs and cats due to their response to allergens. In dogs, the predominant symptom is itching as the skin plays a vital role in its reaction to allergies. During an allergic reaction, the mast cells in the skin break down (de-granulate) causing a release of chemicals, like histamine, that causes the skin to itch and the dog to scratch. In cats, we don’t see this as dramatic. The respiratory system is mostly affected due to inflammatory reactions by the sensitive mucosal linings of the nose, sinus, upper and lower respiratory systems. These differences will help explain how secondary and tertiary problems arise due to allergies. Here are a few.
- Ear infections (secondary). When you look at a dogs ears, what do you see? You see skin. When the skin is itchy due to allergies, the skin inside the ears itch as well. Itching causes inflammation and inflammation causes heat. Ears, due to their anatomy have a horizontal ear canal that stay moist. When heat and moisture join forces, opportunistic organisms like bacteria and yeast proliferate and cause infection. (Tertiary): Auricular hematomas. Ear hematomas are often seen in pets due head shaking from itchy and/or infected ears. These are caused by ruptured capillaries under the skin in the ear flap causing a pocket of blood to accumulate. These need to be drained in order to be resolved.
- Skin infections (secondary). Almost all skin infections are secondary problems. Bacteria and yeast live on the skin and when inflammation occurs due to allergies, the opportunistic organisms move deeper into the layers of skin and cause infection. Many vets treat the skin infections with antibiotics, eliminating the secondary bacterial infection, while exacerbating the yeast infection, as well as damaging the normal gut flora. (Tertiary): Some dogs will actually develop allergies to the bacteria on their skin. We call this staph hypersensitivity and is often treated with staph antigen injections.
- Anal gland impaction (secondary). Anal gland impaction occurs when the skin at the mucosal junction around the anus becomes inflamed, blocking the openings of the anal ducts, much like pinching the end of a garden hose. The anal glands continue to produce fluid and if they cannot empty, they will enlarge to the point of abscess formation which often requires surgical intervention. I have heard people say that they should not have these emptied manually. This is not so. If they cannot empty on their own, we must help them by reducing the local inflammation due to allergies and emptying them to prevent abscess formation. (Tertiary): Hyperkeratosis of the perianal skin. If you look at some senior dogs with chronic allergies you may notice the skin area around the anus is thickened, like leather. This is called hyperkeratosis and is due to chronic inflammation of the area due to allergies. At this point it may become impossible for these dogs to empty their anal sacs. Many have to have them surgically removed in order to resolve the problem.
- Interdigital cyst (secondary). Many dogs have recurring interdigital cysts formed between their toes. We call this chronic furunculosis which means chronic inflammation and deep infection. These cysts are very painful and often require both surgical intervention and long-term antibiotic therapy. (Tertiary): It is common in many breeds like Pugs, for interdigital cysts to form hyperplasia and fibrous masses between the toes. These benign masses due to chronic inflammation will put pressure on the toes and cause them to deviate and roll over on themselves. The deviation of the toes leads to chronic inflammation and arthritis in the digits.
- Eye problems (secondary). It is common to see dogs, particularly, short-nose breeds that come in with acute eye problems secondary to allergies. These dogs will often rub their face on the carpet or furniture in order to relieve the itching and because their eyeballs protrude, the cornea will often get abraded, like a floor burn on your knee. This is very painful and needs to be addressed immediately. (Tertiary). Anterior uveitis is a reactive inflammatory disease of the vascular component of the eye. It is usually caused by trauma to the cornea and if not treated immediately can lead to serious eye problems resulting in glaucoma.
- Sinusitis (secondary). This is a common secondary problem seen in cats with allergies. The inflammation of the delicate membranes that line the sinuses create congestion and potential for sinus infection. Each time a pet has a sinus infection, the mucous membranes become thickened and reduce the ability for the sinus capillaries to supply blood flow to the area. In time, it becomes impossible to deliver medication into the infected area. (Tertiary). Sinus polyps and chronic infection. Very common in cats and people. The polyps are formed due to chronic inflammation and create a great place for bacteria to grow. Due to the damaged blood supply to the area, surgery is often required to open (trephine) the sinus and treat the abscessed sinus.
- Asthma and bronchitis. Asthma is very common in cats and can be life threatening if the bronchi are constricted to the point that the lungs cannot supply oxygen to the body. Asthma is defined as allergies affecting the lungs and must be addressed as such. Symptoms usually include coughing and wheezing. In dogs, we don’t see the typical asthmatic symptoms that we see in cats. However, we often see chronic inflammation of the upper respiratory system causing coughing, retching, spitting up mucous and even reverse sneezing episodes.
There are many other secondary and tertiary diseases associated with allergies and imbalanced immune system in both cats and dogs. The wise vet will connect the dots in hopes of resolving the problems as well as treating the symptoms.