Overview:
Allergy season is a difficult time for many people and pets alike! Many forms of allergies exist and present in different ways. An allergy is an over reaction of the immune system to an allergen (the specific thing the immune system is reacting to). The allergen is the substance the pet develops the allergy to. The allergies can be classed into two very basic categories environmental and food allergies. Environmental allergies include contact allergens, flea dermatitis, and temperate environment allergens such as grasses, pollen and mold-spores. Food allergies attribute to less than 5% of allergies seen in pets, although uncommon, they can be very difficult to pinpoint and treat cohesively. Many pets suffer from a combination of these allergens.
Atopic dermatitis is common name used to describe a pets state during an allergy flare up, it refers to form of skin inflammation caused by an over stimulation of the pet’s immune system caused by an allergen. Dermatitis can be a chronic issue and relapses are common after an initial incident; it is not contagious but is characterized by the common symptom of pruritus (itchiness).
Both dogs and cats can be affected equally by allergens; however some breeds have significantly higher predilections to allergies that are further effected and vary geographically.
The United States has several breeds that are commonly affected by allergens, in no particular order these breeds are: English bulldogs, West Highland terrier, Pugs, Miniature Schnauzer, Lhasa Apso, Irish Setter, English Setter, Dalmatian, Carin Terrier, Boston Terrier, Scottish Terrier, Wire-haired Fox Terrier, and the Golden Retriever. However, no specific cat breeds appear to be likely to develop allergies.
Environments that generate moderate temperatures, high humidity, and large allergen numbers can make animals more susceptible to allergens. These temperate climates provide the best environment for year round allergies as there is little to no seasonal changes. This allows all allergens to be present year round without consequence.
Generally dogs begin to develop signs of allergies between 1-3 years of age, although allergy symptoms may begin as mild irritations, they can become clinically noticeable to owners by the age of 3.
Common Symptoms:
Most common signs observed by clients are scratching, rubbing and licking of various affected body parts. Most common areas for allergies include face and feet. Due to constant mouth contact to the skin, and possible breaking of the skin, skin and ear infections can be present.
Other complications of allergies include;
– Saliva discoloration of hair (rust-brown appearance to light colored hairs)
– Papula reactions (small raised bumps on the skin’s surface)
– Alopecia (hair loss)
– Hyper-pigmentation (darkening of the skin surface)
– Lichenification (thick, hard, calloused skin) {This usually develops in association with hyper-pigmentation}
– Seborrhea (excessively oily or dry skin)
– Conjunctivitis (inflammation of eye tissues)
– Skin crusts (dried discharge left form a skin lesion)
This is not a complete list, your pet may experience one, more, or none of these symptoms and may still be diagnosed with allergic dermatitis by your veterinarian.
Common Causes and Considerations:
Many types of pollen from grasses, weeds and trees are attributed to allergies in pets. Although the most common, other well known allergens in pet’s are mold spores, dust mites, other animal’s dander, and insect bites. The most common insect allergy is to fleas. This specific allergy is known as flea-bite hypersensitivity and causes intense itching even from one or very few bites. Many owners use a combination of pet, house, and yard products to lower the risk of bites to pet’s with this sensitivity. Adverse food reactions are not uncommon, but are less likely than environmental allergies.
Treatments and Medications
Medications listed in this section are to provide a brief overview of potential medications that may be prescribed by your veterinarian for your pet, and is not meant to substitute medical advice from a veterinarian. This list is not all inclusive as there may be other treatments and medications available from your veterinarian that are not listed here. Treatments may vary depending on the medical advice for your pet under the care of their regular veterinarian.
Treatment usual consists of blanket medications to treat symptoms rather than specifically targeting the exact allergen. Specific target treatment can only be accomplished by allergy testing done by an outside laboratory. Treatments can consist of bathing with medicated shampoos to minimize itchiness and unbalanced skin flora, avoid substances to which a pet is allergic (if possible, and if the allergen is known), and switching to a diet high in essential fatty acids (Purina DRM is a great dermatological food high in these sources and was specifically designed with environmental allergies in mind). Changing foods due to a food allergy can be difficult since isolating the specific source is hard without proper allergy testing.
Potential medications can include:
– Immunotherapy (allergy injections)
– Immunosuppresive Medications
– Steroids
– Antihistamines
– Topical sprays
Immunotherapy injections are used once an animals specific allergen has been identified through testing. The laboratory will then make a specific mixture of allergens that your pet is allergic to and administer those through injections or sometimes liquids given under the tongue. The injections will gradually increase the amount of exposure your pet has to those allergens, which will hopefully reduce the pet’s sensitivity. This hypo-sensitization is generally desired if other medications have failed to give lasting relief to the pet. This type of treatment is generally successful to reduce itching by as much as 60-80%. Unfortunately, due to the gradual increase needed for these injections, response is generally slow, requiring between 3 – 6 months of intensive therapy before results are seen. By the end of the first year, a pet’s progress should be much more significant. Of course once a specific allergen has been identified owners should take precautions to remove a pet’s exposure to these substances as much as possible. However, sometimes certain allergens are unavoidable, and therefore require treatment.
Immunosuppresive medications are fairly new to the market in veterinary medicine. These medications suppress the immune systems response to an allergen. The medication will inhibit a specific receptor in the dog that is usually responsible for signaling an allergic response. This response may also include blocking the effect of inflammatory cells to certain areas as well. Apoquel is an example of a medication in this class; this particular medication works rapidly (within 24 hours) and is given daily in slow decreasing doses; with the hope to use the minimum dose needed to keep your pet itch free. Monitoring blood work of a complete blood count (CBC) is recommended every 6 – 12 months, depending on the practice’s protocols. Most practices will require blood work prior to prescribing these medications to ensure no pre-existing conditions exist that would compromise use of these medicines.
Steroids should be given as a short term relief option, mostly used to help stop the cycle of itching and causing secondary infections. Generally these are given at the lowest dose possible as directed by your veterinarian. Steroids may be given in the form of tablets or injections that may last several weeks. Monitoring blood work of a serum chemistry panel every 6 – 12 months is recommended depending on the practice’s protocols. Most practices will require blood work prior to prescribing these medications to ensure no pre-existing conditions exist that would compromise use of these medicines.
Antihistamines are less effective than other medications listed, but can be a good starting point with less severe allergies. There is broad spectrum of antihistamines that include over the counter medications as well as prescription medications. Antihistamines in cats is not as effective as it is in dogs and can cause adverse side effects.
Topical sprays for allergies will generally have minimal effect on severe allergies, but can provide relief for minimal surface allergies. These can be applied to large body surfaces to help with any itching a pet may have.
Follow-Up Care
Patient’s should be monitored by a veterinarian with continued care for the first 2 – 8 weeks of starting medications, and should be evaluated every 6 -12 months as needed depending on your pet’s case. Owners are advised to monitor itchiness, continued scratching or itching and look for drug reactions at home. Owners should be able to determine when an acceptable level of treatment has been reached by medications and continue treatment protocol from there. Once this level is reached, it should be maintained for as long as possible.
Allergies are seldom life-threatening, but can become non responsive to traditional medical approaches, which can cause decreased quality of life for a pet. These determinations should be made by a veterinarian to consider the pet’s well being with their owner. If allergies are left completely untreated, they can worsen over time and cause serious health concerns such as secondary infections that require additional medications and treatments. However, in rare cases, allergies may spontaneously resolve on their own for no known reason. These instances are few and far between and should not be taken as common occurrence. Any pet that shows signs and symptoms of allergies, should be seen by a veterinarian for evaluation.
Summary
Atopic dermatitis is a skin condition that is chronic and progressive. This condition rarely goes into remission, and cannot be cured, only managed by treatments and medications. These therapy treatments and medications may become necessary to maintain a good quality of life for your pet. Always contact your veterinarian with any questions or concerns about your pet’s health. This article is NOT a substitute for veterinary medical advice and should not be used as a guide to diagnosis or medicate your pet without consultation from your veterinarian.
Reference: http://download.skyscape.com/download/ota/5mvetcf5/documents/pdf/atopic_dermatitis.pdf