Animals Have Allergies, Too!
By Melanie Iverson, Dane County Humane Society Animal Medical Services Intern
What is an allergy?
An allergy is a hypersensitivity of the immune system to a normally harmless substance called an allergen. Most of these substances are proteins and may be of insect, plant, or animal origin. Exposure to these substances results in the production of antibodies, which sensitizes the immune system causing an allergic reaction. Most of these reactions involve a specific antibody in the blood called Immunoglobulin E (IgE). When the allergen and antibodies react, potent chemicals such as histamines are released that cause inflammation and symptoms of an allergic reaction. Just as with humans, it is common for both dogs and cats to have allergies. These allergies can be organized into three categories: contact allergy; food allergy; and inhalant allergy.
Common Symptoms
Allergy symptoms in animals are much different than the symptoms of humans. Human allergy symptoms often include sneezing, running nose, and puffy eyes. The most common symptom of an animal allergic reaction is itching of the skin called pruritus. This can be localized or generalized all over the body. The severity of the pruritus can cause serious scabbing and infections on the skin as well as hair loss and increased skin pigmentation. In addition, some animals can show signs of respiratory distress such as coughing, sneezing, and wheezing. Runny discharge from eyes and nose as well as swelling of the eyes can be seen in cats. Other possible symptoms from animals suffering from allergies include vomiting and diarrhea.
Are these signs of allergies?
What is an allergy?
An allergy is a hypersensitivity of the immune system to a normally harmless substance called an allergen. Most of these substances are proteins and may be of insect, plant, or animal origin. Exposure to these substances results in the production of antibodies, which sensitizes the immune system causing an allergic reaction. Most of these reactions involve a specific antibody in the blood called Immunoglobulin E (IgE). When the allergen and antibodies react, potent chemicals such as histamines are released that cause inflammation and symptoms of an allergic reaction. Just as with humans, it is common for both dogs and cats to have allergies. These allergies can be organized into three categories: contact allergy; food allergy; and inhalant allergy.
Common Symptoms
Allergy symptoms in animals are much different than the symptoms of humans. Human allergy symptoms often include sneezing, running nose, and puffy eyes. The most common symptom of an animal allergic reaction is itching of the skin called pruritus. This can be localized or generalized all over the body. The severity of the pruritus can cause serious scabbing and infections on the skin as well as hair loss and increased skin pigmentation. In addition, some animals can show signs of respiratory distress such as coughing, sneezing, and wheezing. Runny discharge from eyes and nose as well as swelling of the eyes can be seen in cats. Other possible symptoms from animals suffering from allergies include vomiting and diarrhea.
Are these signs of allergies?
The symptoms of allergies can be confused with other disorders and can occur simultaneously. It is important to have your animal examined by a veterinarian before taking any steps to treat the possibility of allergies.
Differential diagnoses includes: Parasites (Scabies, Demodicosis, Cheyletiellosis, Pelodera, hookworm dermatitis), folliculitis (bacteria, ringworm, yeast dermatitis), behavioral over-grooming, autoimmune disease, and cutaneous lymphoma.
Contact Allergy
This is the most common type of allergy and results from the direct contact to allergens such as an insect bite or sting. The skin is an easy target for ectoparasites, which have developed ways to pass through the thin layer of the skin to reach the blood vessels. Some insects that can induce an allergic reaction include fleas, blackflies, deerflies, horseflies, mosquitoes, ants, bees, and wasps.
Flea allergy dermatitis is the most common insect-induced allergy disorder. It has no sex or breed predilection and the age of onset is usually 3 to 5 years. The reaction develops from the flea saliva being inserted beneath the skin and causing an abnormal immune response. Only a single fleabite is required to generate an allergic reaction. Scratches and inflammation are a result of self-inflicted trauma due to the itchiness of the bite area. In addition, bacterial infections can easily develop in these areas of tissue damage. Signs and symptoms include evidence of fleas or flea dirt, scabs on the skin and chronic itching leading to hair loss, increased pigmentation, and skin infections. Treatment includes the removal of the fleas and the use of anti-histamines or corticosteroids to block allergic reaction and bring relief. An animal that suffers from a flea allergy should remain on monthly flea preventative year-round.
Food Allergy
This allergy can develop to almost any protein or carbohydrate component of food such as dairy products, beef, gluten, chicken, lamb, and soy. Onset can be variable and symptoms can be variable as well, including pruritus, digestive disorders, and respiratory distress. The particular allergen can be identified using diet trials. The suspected food is completely removed from the diet for up to six weeks and response to treatment is monitored. The only truly effective treatment for a food allergy is the removal of the allergen from the animal’s diet.
Inhalant Allergy
An inhalant allergy is the allergic reaction caused by the breathing of substances such as pollen, house dust, mildew, and molds. This allergy may occur seasonally and can be related to the region of the country in which an animal is found. Onset occurs between 6 months to 3 years of age. Breed predispositions for developing inhalant allergies do exist in dog breeds such as Terriers, Golden Retrievers, Labrador Retrievers, Bulldogs, Boxers, Shar-pei, and Dalmatians at the greatest risk. Most symptoms include itching of face, ears, and paws. An inhalant allergy in an animal can be diagnosed using intradermal skin tests or IgE blood tests. Treatment can vary widely. Options include anti-inflammatory therapy such as corticosteroids and antihistamines that can block the allergic reaction. Hypoallergenic shampoo can be used to soothe and rinse allergens from the animal’s coat. As in human medicine, in severe cases allergy injections can be used to desensitize the immune system from the allergen.
Conclusion
There is not always a clear distinction between what type of allergy an animal suffers from and the cause of its response. Consequently, they are difficult to diagnose accurately. As an animal caretaker it is important to pay close attention to an animal’s behavior and surroundings if you suspect it is suffering from an allergy. It is possible for an animal’s immune system to “grow out” of an allergy, but in most cases an allergy must be monitored and maintained through out an animal’s life. With the correct diagnoses and a course of action plan developed by a veterinarian an animal can lead a happy, healthy life with allergies.
References
Differential diagnoses includes: Parasites (Scabies, Demodicosis, Cheyletiellosis, Pelodera, hookworm dermatitis), folliculitis (bacteria, ringworm, yeast dermatitis), behavioral over-grooming, autoimmune disease, and cutaneous lymphoma.
Contact Allergy
This is the most common type of allergy and results from the direct contact to allergens such as an insect bite or sting. The skin is an easy target for ectoparasites, which have developed ways to pass through the thin layer of the skin to reach the blood vessels. Some insects that can induce an allergic reaction include fleas, blackflies, deerflies, horseflies, mosquitoes, ants, bees, and wasps.
Flea allergy dermatitis is the most common insect-induced allergy disorder. It has no sex or breed predilection and the age of onset is usually 3 to 5 years. The reaction develops from the flea saliva being inserted beneath the skin and causing an abnormal immune response. Only a single fleabite is required to generate an allergic reaction. Scratches and inflammation are a result of self-inflicted trauma due to the itchiness of the bite area. In addition, bacterial infections can easily develop in these areas of tissue damage. Signs and symptoms include evidence of fleas or flea dirt, scabs on the skin and chronic itching leading to hair loss, increased pigmentation, and skin infections. Treatment includes the removal of the fleas and the use of anti-histamines or corticosteroids to block allergic reaction and bring relief. An animal that suffers from a flea allergy should remain on monthly flea preventative year-round.
Food Allergy
This allergy can develop to almost any protein or carbohydrate component of food such as dairy products, beef, gluten, chicken, lamb, and soy. Onset can be variable and symptoms can be variable as well, including pruritus, digestive disorders, and respiratory distress. The particular allergen can be identified using diet trials. The suspected food is completely removed from the diet for up to six weeks and response to treatment is monitored. The only truly effective treatment for a food allergy is the removal of the allergen from the animal’s diet.
Inhalant Allergy
An inhalant allergy is the allergic reaction caused by the breathing of substances such as pollen, house dust, mildew, and molds. This allergy may occur seasonally and can be related to the region of the country in which an animal is found. Onset occurs between 6 months to 3 years of age. Breed predispositions for developing inhalant allergies do exist in dog breeds such as Terriers, Golden Retrievers, Labrador Retrievers, Bulldogs, Boxers, Shar-pei, and Dalmatians at the greatest risk. Most symptoms include itching of face, ears, and paws. An inhalant allergy in an animal can be diagnosed using intradermal skin tests or IgE blood tests. Treatment can vary widely. Options include anti-inflammatory therapy such as corticosteroids and antihistamines that can block the allergic reaction. Hypoallergenic shampoo can be used to soothe and rinse allergens from the animal’s coat. As in human medicine, in severe cases allergy injections can be used to desensitize the immune system from the allergen.
Conclusion
There is not always a clear distinction between what type of allergy an animal suffers from and the cause of its response. Consequently, they are difficult to diagnose accurately. As an animal caretaker it is important to pay close attention to an animal’s behavior and surroundings if you suspect it is suffering from an allergy. It is possible for an animal’s immune system to “grow out” of an allergy, but in most cases an allergy must be monitored and maintained through out an animal’s life. With the correct diagnoses and a course of action plan developed by a veterinarian an animal can lead a happy, healthy life with allergies.
References
- Ward, Ernest DVM. Allergy- General in Dogs. Retrieved from www.vcahospitals.com
- Eldredge, D.M., Carlson, D.G., Carlson, L.D., Giffin, J.M. (2007). Cat Owner’s Home Veterinary Handbook. Hoboken, NJ: Howell Book House.
- Caceci, Thomas DVM. (2008). Flea Bite Dermatitis. Retrieved from http://www.vetmed.vt.edu/
- Skin Vet Clinic. (2012). Flea Allergy Dermatitis. Retrieved from www.skinvetclnic.comfleaallergydermatitis.html
- Medleau, L., Hnilica, K.A. (2006). Small Animal Dermatology: A Color Atlas and Therapeutic Guide. Philadelphia, PA: Elsevier Health Sciences.