Learning About Allergies

Allergy is a disease in which the immune system reacts abnormally to everyday substances such as pollens, animal danders, mold spores, mites or certain foods. All of these allergic reactions are unpleasant, some are serious, and a few can be fatal. The offensive substances causing allergies are known as allergens. An allergic reaction may be caused by inhaling or ingesting the allergen or may be the result of direct contact with the allergen.

»	What Are the Signs of Allergy?
»	How Do Dogs Get Allergies?
»	When are Allergies Most Likely to Occur?
»	Can Allergies be Prevented?
– Keeping Your Home Free of Fleas – Common Fungi/Molds – Controlling Storage Mite Exposure – Controlling House Dust Mite Exposure
»	How Do I Know if My Pet Has Allergies?
»	How Are Allergies Treated?
»	How Successful is Treatment?

What Are the Signs of Allergy?

The most common signs of allergy in pets are scratching, face rubbing, biting and chewing at the skin. Usual locations for signs of allergy are the flank, feet, face, particularly around the eyes, mouth and ears, as well as areas around the base of the tail. In dogs, allergies are often the underlying cause of persistent skin disease, however, it is important to note that not all scratching is due to allergy. Conditions such as thyroid disease, fleas and certain infections, such as ringworm, can cause similar signs.

How Do Dogs Get Allergies?

Most dogs with allergies inherit the tendency to produce allergen-specific IgE in response to an allergen from their parents. After continued exposure to the offending allergens for months to years, the signs of allergy become apparent in the pet. The typical allergic pet starts with a short period of biting and chewing the first year which may be mild or perhaps unnoticeable. With repeated exposures to the offending allergens, the pet gradually experiences prolonged periods of discomfort and more severe signs.

When are Allergies Most Likely to Occur?

Allergies occur whenever the offending allergens are present. The more common allergens, such as house dust mites or mold spores, will produce signs of allergy year round, while allergies from plants that pollinate during warm months are apt to cause allergies only when they pollinate. Food allergy may occur by itself or it may be a component of an overall allergy problem. Because of the complexity of allergy diagnosis, the combination of patient history, physical examination and allergy signs in the pet are all important in making an accurate diagnosis.

Can Allergies Be Prevented?

Since the tendency to produce IgE in response to specific allergens is inherited, there is no absolute way to prevent allergies. It is therefore generally accepted that allergies can be controlled but not prevented. The best control is achieved through avoidance of the offending allergens. For example, if your pet is allergic to fleas, it is better to prevent flea infestation. However, allergens like molds and mites are virtually impossible to avoid, resulting in the need for alternative allergy treatments.

Keeping Your Home Free of Fleas

» Printable PDF

Fleas are one of the most common causes of pruritic or itchy skin disease in pets. There are two ways fleas can cause a pet to itch. The presence of the fleas crawling around in the fur causes the pet to scratch and bite the skin. Once the pet starts itching, the self trauma to the skin causes the pet to itch more. If the physical presence of fleas is not enough to make the pet itch, some pets are also allergic to the saliva of the flea. Many pets are extremely sensitive to the saliva from the flea bite although the pet may have little evidence of flea infestation. These animals may develop a condition known as flea allergy dermatitis (FAD). FAD is a very pruritic disease and predisposes the pet to secondary bacterial or yeast infections of the skin. Because the pet is so pruritic they groom themselves excessively, eliminating any evidence of fleas. A couple of flea bites every two weeks are sufficient to make a sensitive pet very pruritic without any physical evidence of fleas. FAD should be considered a progressive disease, with each “flea season” resulting in an increasingly severe reaction in the allergic pet. A well-planned flea control strategy is essential to maintaining the health and comfort of both the pet and the owner. Pets that have FAD may never reach a level of zero itchiness, so flea control should be directed at trying to keep fleas off of the pet (see links below for more information).

Appropriate flea control strategy targets all stages of the flea life cycle: eggs, larvae, pupae and adults. Adult fleas emerge from their cocoon and attach to the first host that appears. A pet’s thick hair coat and warm body temperature make the dog or cat an ideal host for the adult flea. The adult fleas lay their eggs on the pet, and the eggs fall off the pet into the carpet, bedding or wherever the pet lies down. The flea eggs hatch into larvae which are very sensitive to light and heat and consequently seek out hiding places, such as cracks in the floor, between carpet fibers, under furniture and under organic material in the kennel. Larvae become pupae and will remain in that state for up to six months until they hatch into adult fleas. Because the flea spends most of its life cycle off of the pet, environmental control should be aggressive.

Environmental controls include frequent: vacuuming and mopping all floors, washing kennel floors, washing the pet’s bedding, commercial extermination and outdoor spraying every 2-3 weeks. All pets should be removed from premises during environmental treatments.

Fleas tend to seek dark, cool places. Moderate temperatures with relatively high humidity (70% or higher) make fleas mature faster, while less ideal conditions tend to slow the growth progress.

Although adult fleas are discriminating about their hosts, all of the pets and humans in an infested home are vulnerable. To be successful, a flea control program must involve the entire household, and ALL animals in contact with the affected pet should be treated.

There are many choices for flea control. Insecticides are the most common form of treatment for adult flea infestations and are necessary to eradicate fleas from the animal. Other methods such as insect growth regulators work to eliminate fleas in the egg and larval stages and may be useful in addition to environmental treatment. Your veterinarian can advise you on which combination of products will work best for you.

Goals when treating for flea infestation are to eliminate fleas from the pet, the environment and prevent infestation or re-infestation of the environment and pet:

Keep grass short and remove any organic debris from the yard and keep kennel areas clean.
Block off access to crawl spaces under the house or porch and treat these areas with insecticides. Also remember to treat any shaded areas in which your pet may lie.

Note: Fleas may be responsible for the transmission of several diseases hazardous to humans and pets.

More information on fleas can be found at:

http://www.cdc.gov/nasd/index.html
http://www.vetmed.iastate.edu/animal_owners/animal_health/dermatology/index.html
http://www.oznet.ksu.edu/library/entml2/samplers/mf760.asp

Common Fungi/Molds

» Printable PDF

Fungi are saprophytic and parasitic plants found both indoors and outdoors in moist organic materials. Fungi include mold spores and their vegetative forms, mildews, rusts, smuts, mushrooms, toadstools, yeast and slime molds.

OUTDOOR SPORE LEVELS vary throughout the day and year. Because levels are often higher near the ground, lawn mowing and grain harvesting result in marked dispersion of mold/fungal particles. Mold allergic animals may develop clinical signs following exposure to leaf litter, peat moss, mulches, soil, rotting logs, grain bins, silos, hay, ensilage and compost piles. Alternaria and Cladosporium are the principal outdoor molds. Aspergillus, Dreschleria, Fusarium, Penicillium and Stemphyllium may also be found outdoors.

INDOOR MOLD LEVELS are commonly elevated when indoor air quality is poor such as when the house is closed for heating purposes during cold weather or when air conditioning is used during the summer. Mold exposure from food residue and tracked-in yard debris within the home may be increased when the relative humidity within the home is greater than 50%.

Cool mist vaporizers, furnace humidifiers and ultrasonic units are often contaminated with fungal growth. Well recognized areas for mold growth in the home include bathrooms, laundry rooms, basements, closets, stored food, refrigerator drip trays, houseplants and potting soil, air conditioners and swamp coolers, humidifiers, garbage pails, mattresses, upholstered furniture, wallpaper, foam rubber pillows, textiles, air vents, shower curtains and interior and exterior walls. The clothing of people working in bakeries, breweries, barns, dairies, greenhouses as well as loggers, mill workers, carpenters, furniture repairers and upholsterers often contains mold spores. Aspergillus, Fusarium and Penicillium are predominate indoor molds. Alternaria, Cladosporium, Dreschleria and Stemphyllium can also be found in building interiors.

INDOOR MOLD CONTROL consists of general cleanliness, reducing excessive indoor moisture (relative humidity less than 50%), and identification and remediation of known mold sources.

For more detailed information please refer to: http://www.heska.com/allercept/client_info.asp
Additional Information: "A Brief Guide to Mold, Moisture, and Your Home"http://www.epa.gov/mold/moldguide.html
"Mold Prevention Strategies and Possible Health Effects in the Aftermath of Hurricanes and Major Floods" MMWR June 9, 2006/Vol.55/No.RR-8
http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5508a1.htm
"Appendix B—Introduction to Molds"
http://www.epa.gov/mold/append_b.html
"Molds"
http://nlm.nih.gov./medlineplus/print/molds.html
"Controlling Mold Growth in the Home"
http://search.oznet.ksu.edu:81/main/query.html?qt=mf2141&Submit=Search
"Tips to Remember: Outdoor allergens"
http://www.aaaai.org/patients/publicedmat/tips/outdoorallergens.stm
"Allergies to Mold"
http://www.njc.org/disease-info/diseases/allergy/about/allergic-to/mold.aspx
"About Seasonal Allergies"
http://www.njc.org/disease-info/diseases/allergy/living/seasonal/index.aspx

References:
Ready, Lloyd M., Miller, William H. Jr., and Willemse, Tom, Allergic Skin Diseases Of Dogs And Cats, Second Edition. W.B. Saunders Company, Philadelphia, 1997.

Pearlman, David S., Shapiro, Gail G., Busse, William W. (authors), Bierman, C. Warren (editor), Allergy, Asthma, And Immunology From Infancy To Adulthood, Third Edition. Elsevier Health Sciences, 1996.

Controlling Storage Mite Exposure

» Printable PDF

Storage mites were first found in grain silos where they thrive in and feed on dry grains. Farmers and workers in environments where hay and grain are stored and handled may develop an allergic sensitivity to these mites. Storage mites are often found in grain bins and dry feed stuffs including dog and cat food. Pets exposed to stored product mites by consumption of food containing these mites are therefore at risk of sensitization and allergic reaction. Storage mite bodies and mite feces are a source of potent allergens. Dogs and cats may be exposed to mite body parts and excreta through inhalation and percutaneous absorption of such allergens.

One of the storage mites, Tyrophagus putrescentiae, the mold mite, is very common but usually goes unnoticed except in occasions when it becomes abundant. Mold mites only develop where there is moisture or high humidity. Infestations have been found in cheese, flour, grain, seeds, bulbs, straw, wallpaper, furniture, dried fruits, and cereal foods. Since even dry foods have some amount of moisture (usually around 10%) they are susceptible to mold and provide an optimum breeding ground for the storage mites. Hypersensitivity to storage mites is a worldwide problem. Data and information regarding allergy to storage mites has increased rapidly over recent years.

Hyposensitization therapy can be effective in atopic patients with storage mite allergy. Some patients are sensitive only to mites, and in these cases immunotherapy is highly effective. In addition, an effective environmental control regimen can prove useful in minimizing the patient's discomfort and lessening immediate signs of allergy.

Although it is virtually impossible to totally eliminate storage mites from the environment, steps can be taken to inhibit their multiplication and thereby minimize exposure to storage mite allergens.

The following suggestions should prove useful in controlling storage mite populations:

Store pet foods in airtight containers. Avoid storage of pet food in garages, sheds or basements.
Do not use old or outdated pet food. Check food for dust, mold or odors and remove questionable food from the house and discard immediately.
Wash food containers frequently in detergent and HOT (130 F) water. Dry completely before refilling with food.
Dispose of pet food bags immediately outside of the house.
Do not stockpile foods. Purchase only what is needed for 30 days at a time.
Avoid keeping fruit and other foods that can mold on the counter.
Check food bags for tears or holes prior to purchase.
Low quality pet foods with a high quantity of particulate debris at the bottom of the bag should be avoided.

References:

Reedy, Lloyd M, Miller, William, H Jr., and Willemse, T ALLERGIC SKIN DISEASES OF DOGS AND CATS. 2nd Ed W.B. Saunders Company, Philadelphia, 1997

Websites for additional information:
www.umass.edu/soph/allergyfx.txt
www.sel.barc.usda.gov/acari/content/watermite/rotate.html

Controlling House Dust Mite Exposure

» Printable PDF

House dust mites (Dermatophagoides sp) exist throughout our environment. These microscopic creatures feed on human and animal dander, skin scales and hair. They are commonly found in beds, mattresses, carpets, sofas and pet bedding. Mites multiply rapidly when a house is sealed because the temperature and humidity are mite-optimum (50-70% relative humidity). Mite bodies and mite feces are the principal source of house dust mite allergens.

Hypersensitivity to house dust mites is a widespread problem in allergy. Approximately 50-60% of all dogs with elevated allergy test results to other allergens also exhibit elevated results to mites. Hyposensitization therapy can be effective in the reduction of symptoms in atopic patients with mite allergy. Some patients are sensitive only to mites, and in these cases immunotherapy is highly effective. In addition, an effective environmental control regimen can prove useful in minimizing the patient's discomfort and lessening immediate signs.

Although it is virtually impossible to totally eliminate house dust mites from our environment, we can take steps to inhibit their multiplication and thereby minimize the effect on the animal who is allergic to house dust mites.

The following suggestions should prove useful in controlling mite populations. Although some of these suggestions may be difficult to apply to the entire household, it is recommended that at least the main sleeping areas of the allergic pet be maintained according to these specifications.

Avoid the use of carpeting. Base floors, such as hardwood, vinyl or tile are best; if carpet must be used, low pile is preferable.
Remove upholstered furniture, books, records, piles of newspapers and magazines, knick-knacks, stuffed animals, wall hangings and other "dust collectors" from the room.
Wash all bedding frequently (at least weekly) in HOT (130 F) water.
The bedroom has been found to have the greatest concentration of mites. A recent study demonstrated over 45% of US homes have bedding with dust mite allergen concentrations that exceed a level associated with allergic sensitization. It's best to keep your pet out of the bedroom. Encase mattresses and box springs in airtight plastic; seal zippers on the casing with tape. Use washable blankets and mattress pads. Encase pillows in 10 m pore fine woven or vapor - permeable covers. Note: the most dust-free type of bed is a waterbed.
Plants can also be dust collectors and should be removed.
Change furnace and air conditioning filters frequently. Electrostatic filters may be more effective in filtering out dust, mites and inhalant particles.
Use air conditioning to control the temperature during warm months. Central air conditioning is preferred, but window units are also helpful. Try to maintain the humidity levels between 30 and 50%. Dehumidifiers may prove useful.
Dry steam clean and vacuum carpets and upholstered furniture at least weekly using good quality 2 layer bags or high efficiency particulate air filters. Steam cleaning is believed to kill the mites while vacuuming removes them. Wet mop and dust with a damp cloth daily. Room should be properly aired after vacuuming.
Groom animals frequently.

Ref.

Eggleston PA, Bush RK. Environmental allergen avoidance: An overview. J Allergy Clin Immunol 2001;107:S403-5.

Arlian LG, Platts-Mills,TAE. The Biol of Dust Mites and the Remediation of mite allergens in allergic disease. J Allergy Clin Immunol 2001;107 No 3:S406-13 Study Shows Simple Steps Can Reduce Dust Mite Allergens in Bedrooms: www.intelihealth.com. August 6, 2001.

Websites for additional information:
www.intelihealth.com
www.pollen.com
www.niaid.nih.gov/publications/allergies.htm

How Do I Know if My Pet Has Allergies?

If your pet is persistently chewing its feet or scratching at its face, allergy may be a possible cause. Unfortunately, there are no specific signs for allergy so you will need to rely on your pet's veterinarian to make that determination. Allergy diagnosis requires eliminating other causes for your pet's clinical signs. This involves taking a detailed history of your pet's problems, a complete physical examination and some preliminary laboratory tests. If your pet's history and physical examination suggest that an allergy is likely, your veterinarian may recommend allergy assessment to identify the offending allergens.

How Are Allergies Treated?

There are a number of different ways or combinations of ways to treat allergies. If the allergy is mild, control may be achieved through the use of methods to avoid contact with the offending allergens and medications to control the clinical signs. In pets with more severe allergies, or in pets where allergies occur year round, specific immunotherapy (allergy shots) may be needed. Immunotherapy is often recommended because prolonged use of certain medications, especially steroids, reduces itching, but produces serious side-effects which may decrease the quality and length of your pet's life. Your pet's veterinarian will discuss various alternative treatments with you based on your needs and the needs of your pet.

How Successful is Treatment?

The success of treatment depends on several factors including the overall health of your pet, and a commitment to therapy. In general, the steps to successful allergy treatment involve the following: (1) trying to avoid or reduce the allergens in the environment, (2) giving recommended medications to control clinical signs and (3) identifying the specific allergens causing clinical signs in your pet early in disease, followed by allergy immunotherapy. The combination of these therapies will result in successful allergy treatment in the majority of pets.

Visit your veterinarian if you suspect your dog may have an allergy.

back to top