Allergies in Dogs Symptoms

The symptoms of allergies in dogs arise as a result of an allergic response; the immune system of a dog predisposed/presensitized to a given allergen, experiences an hypersensitivity reaction on re-encountering the same allergen. As was noted in Do Allergies Result From Nature or Nurture?, although science has unraveled various pieces of the allergy jigsaw, at present the picture is far from complete and much remains unclear about this complex and diverse condition e.g. precise role played by genetics or the interplay of various factors such as other allergens, diseases and even geolocation etc.

Given that the immune system and underlying allergy mechanism for both dogs and people share much commonality, one might assume that many of the symptoms observed in dogs parallel those for people and vice versa e.g. inflammation, itchiness, pain and discomfort, redness and rashes associated with histamine and other allergy chemical mediators. As was discussed in the section concerning allergic to dogs symptoms i.e. people with allergies to dogs, we discovered that the symptoms of allergies can include:

• Allergic Rhinitis e.g. sneezing or nasal congestion.
• Allergic Conjunctivitis e.g. inflamed eyes.
• Allergic Skin Conditions: This includes atopic dermatitis, allergic contact dermatitis (ACD), and allergic dermatitis related to external parasites/food/microorganisms (e.g. fleas/wheat/bacteria), as well as less common but serious skin conditions including urticaria (hives, welts or wheals) and angioedema (swelling). Dermatitis is the term that refers to inflammation of the skin.
  The most common allergy related dermatitis in dogs is canine atopic dermatitis and this is typically associated with dust and dust mites, various pollens and mold spores. Jaeger et al.2010 noted that the most common locations for lesions associated with atopic dermatitis were paws (62%), ventrum (51%) [underside or belly], ears (48%) and face (39%).
• Allergic Asthma  e.g. wheezing.
• Chest Congestion e.g. persistent cough with discolored mucus.

In addition, we discussed how allergies can impact one’s quality of life, the issue of anaphylaxis as well as various other possible signs and symptoms. Moreover, we discussed the variability of allergy symptoms which is an issue equally applicable to both people and dogs. With reference to dogs:

• Differences in the frequency/severity of the allergy response and the type of symptoms that develop may vary not only between dog breeds (e.g. certain breeds such as Retrievers, Setters and Terriers appear to be more likely to be affected by allergies) but they can be highly individual and are subject to the interplay of numerous factors e.g. the dog’s genetic make-up, the cause or source of the allergens, and how the allergy sufferers come into contact with allergens (direct or indirect skin contact, ingestion, inhalation) etc.

Symptom variability can be impacted by both the health of the individual’s immune system and their age:

• The intimate relationship between the immune system and allergy mechanism was discussed in the section Understanding Dog Allergies, and in many ways allergies are representative of an overly active immune system. Therefore, logic would suggest that in the case of an individual whose immune system is compromised and weakened e.g.due to serious disease or certain medications, their allergies would lessen. However, although this is the situation for some individuals, others develop more notable symptoms at such times.
• Also, some dogs with an existing allergy – particularly inhalant allergies – are more likely to get others as they age (even though their immune systems may be gradually getting weaker), whereas others are not affected. Moreover, a dog may suffer allergies when young, that disappear in their middle years, only to return in old age.
• Treating allergies in older individuals can be problematic due to the interaction of allergy medication with other medical conditions e.g. antihistamines associated with an enlarged prostate or heart conditions.

Therefore, despite what you may read on certain internet sites as implied statements of fact e.g. “as all dogs get older, their allergies worsen” or even conversely “allergic reactions definitely decrease with age”, the reality is that symptom variability is highly unpredictable, complex and the science to explain it is currently far from complete. Aside from the variables noted above, many other questions remain unanswered. For example, what impact do changing climate patterns have on airborne allergens, or what effect are potent “super antigens” – such as car exhaust fumes linked to mold – having on allergy sufferers? etc.

Although the points/issues noted above apply to both dogs and people, differences do exist between the allergy profile of canines and humans. Variations in physiology, anatomy and the manner in which a given symptom is expressed all play a role. For example, dogs are particularly prone to experiencing skin and ear flap (pinna) allergy symptoms because they have a higher proportion of skin mast cells (release various chemical mediators) than humans (Garriga et al.1998, Asti et al. 2005). Moreover, a person who experiences itchy skin will probably scratch it using their hands, whereas a dog may be seen to alleviate the problem by repeated licking or chewing of the troublesome area.

The following lists various signs/symptoms and associated conditions relating to allergies in dogs that will be covered in depth in subsequent articles. However, with regards to best practice advice, any person concerned about their dog’s allergy symptoms should always consult a veterinarian or other professional in the field e.g. veterinarian dermatologist for dog skin related problems.

COMMON ALLERGY SYMPTOMS AND CONDITIONS:
	Itchiness (Pruritus) Learn about allergy related itchiness (pruritus) and its various manifestations in dogs including increased scratching and rubbing, licking, nibbling and chewing, shaking as well as itchy and irritated eyes.
	Airways and Respiratory, Gastrointestinal, Nasal and Emotional Well-Being Other common signs and symptoms of allergies are airways and respiratory issues, gastrointestinal (difference between a food intolerance and a food allergy), nasal and those impacting both physical and emotional well-being.
LESS COMMON BUT MORE SEVERE ALLERGY SYMPTOMS AND CONDITIONS:
	Urticaria, Angioedema and Anaphylaxis Most allergy sufferers only experience relatively mild symptoms but some are not so fortunate and develop hives/welts/wheals, swelling issues and even life-threatening anaphylaxis.
OTHER ALLERGY SYMPTOMS AND CONDITIONS:
	Enlarged Lymph Nodes (Lymphadenomegaly or Lymphadenopathy) The lymphatic system is an important component of both the circulatory and immune system. Enlarged lymph nodes can develop due to various conditions including allergies. Learn more here.
	Eosinophilic Conditions Affecting Dogs A range of canine eosinophilic conditions exist involving elevated levels of eosinophils (type of white blood cell) and who cause is believed to involve hypersensitivity.
ALLERGY RELATED SYMPTOMS AND CONDITIONS:
	Secondary Infections, Hot Spots and Lick Granulomas Aside from secondary infections, allergy related symptoms and conditions that can affect canines include hot spots and lick granulomas. Though not uncommon, such conditions should never be taken lightly.
	Dog Fever Learn about dog fever (dog pyrexia) – How to tell if a dog has a fever, normal dog temperature and grades of fever, dog fever symptoms and dog fever treatment.