By far the most common allergies are flea allergies and environmental allergies. In people the area most commonly affected is the respiratory system, often recognized by what we commonly call hay fever. In the dog, while the respiratory symptom is occasionally affected, it is not the most common target of allergies. The target organ is the skin, causing intense reaction that is painful. What we observe is intense itching, biting, chewing or licking at a particular area of the body. Though these manifestations may appear different, they all are caused by the pain associated with allergies.
While the skin is the target organ, different type of allergies tend to affect different areas of skin. This helpful to identify the type of allergies in formulating a treatment plan. While this is helpful, it is not absolute and often patients have multiple types of allergies or may have symptoms that cross over.
Flea allergies are the most common allergy experienced in pets. This condition is a hypersensitivity to the proteins or antigens found in flea saliva. When a flea bites a cat or dog, a small amount of saliva is released and triggers a reaction from your pet’s immune system causing extreme itchiness and skin irritation throughout the body. When these animal are examined, rarely will you find a single flea. The reason is the flea causes such intense pain the dog or cat will seek out the flea and try to destroy the flea. Fortunately, flea allergies have a characteristic pattern that helps easily make the diagnosis in most cases.
The typical skin pattern is chewing from the base of the tail up to the middle of back in severe cases. In most cases the chewing is so severe that there is a loss of hair. If the pet appears to be losing hair, you can feel the stubble of broken hairs from chewing the area.
There are two other diseases that cause this pattern. One is flea bite dermatitis which is caused by massive number of fleas on the patient. This is still a flea related problem and is diagnosed by the massive number of fleas and flea dirt present. The other problem is this chewing pattern in rare cases is associated with anal glands which is evaluated during the examination.
The first thing in treating these dogs is proper flea control. Shampoos, flea collars, soaps, sprays and topical preparations including Frontline do not work. After 25 years, fleas have become resistant to the effects of Frontline. Currently in dogs the product I recommend is Bravecto, which will provide three months of protection. In cats I recommend either Bravecto, which will give three protection, or Revolution Plus applied monthly. I prefer Revolution not because of flea control but it provides better control for our cats. These patients should have year round flea control because on any day over 60 degrees fleas may hatch out. In Missouri there are many winter days over 60 degrees.
Proper control is important but only corrects half the problem in the beginning. However, there is intense reaction and often associated infection in the skin that needs to be resolved. Any infection present needs to be treated with antibiotics. Depending on the severity of the injection, antibiotics are used for two to six weeks.