Allergic skin disease, or atopic dermatitis, is an extremely common skin disorder in dogs and occasionally occurs in cats. In my practice, it is probably the #1 skin problem we treat. Many of the affected dogs have not only primary atopic dermatitis, but secondary problems including bacterial and yeast dermatitis as well. 

Diagnosis of the atopic pet is usually easy. The classic sign of itching without primary skin lesions points towards a diagnosis of atopy (other rule-outs would include food allergy and occult sarcoptic mange). Atopic dermatitis should also be suspected with chronic skin infections, including ear infections. 

The conventional treatments have relied on corticosteroids and antihistamines. While effective, there are numerous side effects of corticosteroids including increased thirst and urination, increased appetite, weight gain, Cushing's disease, Addison's disease, osteoporosis, increased susceptibility to infection, fatty liver disease, diabetes mellitus, gastrointestinal ulceration, cartilage degradation, and blood chemistry anomalies. Side effects of antihistamines are less common but include sedation and failure to control the itching. 

Complementary therapies are used to reduce or preferably eliminate the need for chronic drug therapy, allowing resolution of the itching without the troubling side effects so often seen with conventional treatments. They include: 

Topical treatment - A very important part of therapy for atopic pets is external decontamination using various shampoos, conditioners, and "leave-on" residual products. The most benign include ingredients such as aloe vera and colloidal oatmeal. More stubborn cases might require the addition of pramoxine, antihistamines, or corticosteroids. Frequent use is essential to minimize antigen exposure by the pet, thus reducing the need for systemic medications. 

Fatty Acids - What once seemed bizarre or complementary is now accepted as part of the conventional approach to treating atopic disease by most doctors. Still, being a nutraceutical, fatty acid therapy could fit under the banner of complementary treatment. We still don't know what is the best fatty acid, or even the best dose. I have been using omega-3 fatty acids at double to quadruple the label dose. Some experimentation with the various products might be needed. 

Antioxidants - Higher doses of vitamins C, E, and A offer relief for some atopic pets. They function to detoxify histamines, optimise adrenal function, decrease integumentary cell destruction, and optimise function of the immune system. Because antioxidants can alter blood levels of cortisol and thyroxine, a blood profile checking for adrenal and thyroid diseases is important. 

Enzymes - Some pets respond to health blend formulas, enzyme preparations, and barley grass supplementation. 

Diet - While hypoallergenic diets can help pets with food allergies, they are not routinely prescribed for atopic pets. A trial dose using one of these diets might lower the itching in pets with both food allergy and atopy; diets with fatty acid  supplementation might also help atopic pets. Finally, most complementary doctors would suggest a trial dose of homemade rather than processed food, or at least a "natural" processed food. These "preservative-free" diets can reduce itching in some pets. At some point in the treatment of the pruritic pet, before giving up and resigning the pet to a life of corticosteroids, try a homemade diet using fresh ingredients. Some pets respond dramatically just to this simple 

Homeopathy - homeopathy involves the use of extremely diluted substances to heal the body through the release of vital energy. The rule in homeopathy is that "like treats like", so a thorough history, examination, and laboratory testing are needed to properly choose the correct remedy. Here are some remedies that may prove helpful in treating dogs and cats with atopic dermatitis: Sulphur (Sulfur), Hepar Sulph, Arsen Alb, Rhus Tox. 

Acupuncture - By stimulating specific acupuncture points, you are able to help stimulate the pet's immune system and reduce the itching and inflammation associated with allergic dermatitis. 

Herbal Therapy - Both Chinese and Western herbal therapies can be useful in treating the atopic pet. It is important to try different herbs or combinations in order to match the correct therapy with the pet (similar to other complementary therapies). I have had most experience with Chinese herbal formulas. While I usually am able to treat pets with other therapies without the use of herbs, some owners prefer herbal medicine and some cases require a trial with herbs if they do not respond to other therapies. 

Several herbs that may be helpful include: Scutellaria, Tribulus Anemarrhena, Capillaris. There are many options for the doctor when treating atopic pets. Some pets respond well to complementary therapies as the sole treatment, whereas other pets may still require medications but can get by with lower dosages if using a complementary therapy as well. 

Each doctor will develop his own preferences for treatment. With time, those therapies that seem most beneficial will become the "favoured" complementary therapies for pets with atopic dermatitis. As in every case involving complementary therapies, the challenge is to find the best treatment for each case; having a very understanding owner is critical to success!

© Shawn Messonnier, D.V.M.
Dr. Shawn Messonnier is a nationally known veterinarian, author, and speaker. He is the author of the Pet Care Naturally series of books published by Avery publishing 






Atopy (Allergic Inhalant Dermatitis)

Allergic reaction by the animal to something it inhales such as pollen, house dust mites and mold

Licking of feet, inflamed ears, itching, redness, sometimes development of infection or hot spots

Intradermal or serologic (blood) testing for allergies

Reduce exposure to allergen (what the pet is allergic to), steroids, fatty acid supplements, antihistamines, shampoos, immunotherapy

Food Allergies

Allergic reaction to something in the diet

Licking of feet, inflamed ears, itching, redness, sometimes development of infection or hot spots

Food elimination trials

Change in diet

Allergic and Irritant
Contact Dermatitis

Reaction of the pet's skin to something it had contact with such as wool or plastics

Red skin and small bumps or blisters on the areas of skin that are sparsely haired and directly exposed to the offending substance, itching

Patch test, exclusion trials

Restrict exposure to the allergen or contact irritant in the pet's environment, steroids, antihistamines

Flea Allergy Dermatitis
(Flea Bite Hypersensitivity)

Severe reaction by the animal to the saliva of the flea

Intense itching, redness, hair loss; sometimes development of infection or hot spots

Presence of fleas; reaction to intradermal testing

Flea Control in the environment and on the pet; steroids and antihistamines for the itching

Sarcoptic Mange

Infection with the Sarcoptes mite

Intense itching and self-trauma

Skin scraping and microscopic examination - the mite is often very difficult to find

Amitraz (Mitaban) dips (off-label use*); ivermectin (off-label use*)

Demodectic Mange
in Dogs

(Red Mange)

Infection with the Demodex mite - occurs when the immune system is deficient

Hair loss, scaliness, redness, pustules, ulcers, sometimes itching

Skin scraping and microscopic examination

NO Steroids!

Amitraz (Mitaban) dips

Cheyletiella (Rabbit Fur Mite) Mange

Infection with the Cheyletiella mite

Itching, scaliness

Skin scraping and microscopic examination - the mite is often very difficult to find

Permethrin (Dogs ONLY) or Pyrethrin


Infection with several types of fungus

Hair loss, scaliness, crusty areas, some itching


Miconazole, lime sulfur dips; oral griseofulvin or itraconazole

Yeast Infection

Infection with, most commonly, Malassezia; usually follows some other underlying disease

Itching, redness, sometimes oiliness

Skin scraping/smear and microscopic examination, culture

Treat underlying disease; oral ketoconazole; miconazole shampoos

Hot Spots: Acute Moist Dermatitis

Result from allergies, flea bites, mange, anal gland disease, poor grooming, ear infections, plant awns or burs, arthritis

Hair loss; red, moist, oozing skin; constant licking or scratching

Physical exam and history

Treat underlying condition; clean area; apply Domeboro solution; topical and/or oral antibiotics and steroids

Cutaneous Lymphoma

Rare type of skin cancer

Itching, ulcers, nodules, redness


Usually does not respond to treatment


Infection with several species of lice

Variable; itching, hair loss, crusts, rough hair coat

Finding lice or nits on skin or hair

Permethrin (Dogs ONLY) or Pyrethrin, ivermectin (off-label use*)

Skin Fold Dermatitis

Occurs where folds of skin touch each other such as lips, vulva, face (in breeds like bulldogs)

Redness, oozing, itching

Physical exam; microscopically examine smear for evidence of infection

Treat any infections; clean areas daily; surgical correction if severe


Infection with the larvae (immature forms) of hookworms

Red bumps, usually on feet, rough foot pads, abnormal nail growth, itching

Physical exam, history of poor sanitation

Treat for intestinal infection; move animal to different environment


Acral Lick Dermatitis
Psychogenic Dermatitis

Self-licking in dogs and cats results in self-trauma; possible causes include anxiety, boredom, stress (e.g., new member in household)

Acral Lick: red, hairless, well-circumscribed lesion usually on forearm; cats: symmetrical hair loss, sometimes ulcers, on abdomen, groin, along the back

Exclude other causes; history important

Relieve underlying cause e.g., anxiety;

Bacterial Infection

Often occurs as a result of another condition

Redness, pustules, bumps, sometimes itching

Microscopic examination of smear; culture

Treat underlying condition; topical and/or oral antibiotics

Ear Mites

Infection with Otodectes

Intense itching of ears, redness, dark crumbly discharge in ears

Direct visual or microscopic examination of ear discharge

Clean ears and apply medication containing pyrethrin (Ear Miticide)

Pelodera Dermatitis

Accidental infection with larvae from a non-parasitic worm that lives in straw and other organic material

Intense itching, redness

Skin scraping and microscopic examination

Remove bedding; mild antibacterial shampoo; steroids if necessary to control itching

Chiggers (Harvest mites)

Seasonal disease caused by larvae of the chigger

Itching, bumps usually on feet, abdomen, folds at base of ears

Visualization of mite larvae or microscopic examination of skin scraping

Permethrin (Dogs ONLY) or Pyrethrin

Canine Atopic Dermatitis

Canine atopic dermatitis (allergic dermatitis, canine atopy) is an inherited predisposition to develop allergic symptoms following repeated exposure to some otherwise harmless substance, an "allergen," such as dust mites or pollen. Most dogs begin to show their allergic signs between 1 and 3 years of age. Due to the hereditary nature of the disease, several breeds, including Golden Retrievers, most Terriers, Irish Setters, Lhasa Apsos, Dalmatians, Bulldogs and Old English Sheep Dogs are more commonly atopic, but many dogs, including mixed breed dogs can have atopic dermatitis. The incidence is increasing both in man and animals. 

Atopic animals will usually rub, lick, chew, bite or scratch at their feet, muzzle, ears, armpits or groin, causing hair loss, and reddening and thickening of the skin. In some cases several skin problems can "add" together to cause an animal to itch where just the allergy alone would not be enough to cause itching. These problems include air borne-allergens (pollens, etc.), allergens in food, and allergens from parasites (fleas, etc.) and also bacterial or yeast infections of the skin. Eliminating some but not all of the problems may allow a patient's itchiness to go away. Therefore it is important to treat any other problems that could be making your pet itch while dealing with allergy. 

Specific diagnosis of atopic dermatitis is based upon the results of intradermal testing and/or in vitro (blood) testing. Many medications can interfere with our ability to properly skin test your pet. Length of time that a medication's effect remain in an animal's body is highly variable; however, basic guidelines for withdrawal of medications are: At least 4 weeks off oral prednisone; 10 weeks after triamcinolone acetonide injection; 14 weeks after methylprednisolone acetate injection; 10 to 14 days off antihistamines; 10 to 14 days off topical steroids (ear drops, ear drops or medication for skin); 2 days off tranquilizers.


  1. Antihistamines: This medication works in 20% of atopic patients. Your pet can take antihistamines for life. The only side effect usually seen is drowsiness. Several types may be tried to find the one best for your pet. Topical antihistamines for the eyes can be helpful in patients with eye allergy (itchy conjunctivitis). Visine A® is one over-the-counter product that can be helpful. 

  2. Avoidance of the allergens: This can be helpful for house dust mite allergies. Pollen exposure can be reduced by using air-conditioning and air filters, avoiding the outside early morning and late afternoon, wiping down with moist cloths after going outside and frequent bathing. 

  3. Oral Steroids (prednisone, cortisone, triamcinolone, etc.): These drugs have many potential side effects and are reserved for adult animals, those with short seasonal problems or where other therapy is not possible or is ineffective. Typically, treatment is started at one dose and then tapered off to every other day usage. 

  4. Topical Steroids: Topical usage is safer than oral usage. It can be very helpful if itching is localized (e.g., eyes, ears). It can be used for more widespread disease in the form of leave-on rinses or lotions (ResiCORT®) or a triamcinolone spray (Genesis®). 

  5. Cyclosporine (Neoral®): This immunosuppressive agent can be used at low doses to treat allergy successfully in about 60% of patients. It can also be used to lower needed dosages of steroids. The major short-term side effect is gastrointestinal upset. The long-term safety is not completely known. The dosage can often be lowered after a few weeks of successful treatment. 

  6. Tacrolimus (Protopic® ointment): This drug is related to cyclosporine. It can be very useful for treating localized itchy areas in atopic dermatitis. It is applied once or twice a day at first, and then frequency is reduced. 

  7. Fatty acid supplements: Certain types of oils can reduce allergic symptoms in some patients. We can give fish oil capsules in conjunction with a low-fat diet or prescribe special prescription diets with the fish oil content raised. This therapy can help improve response to antihistamine therapy. 

  8. Allergen Specific Immunotherapy: This involves giving an allergy vaccine injection that is made up specifically for your pet, usually for the lifetime of the animal. After an initial series of injections, periodic boosters will be needed (every 1-3 weeks). 60% to 80% of animals will improve with the vaccine. Results may not be seen for 3 to 6 months. When results are not seen in 9 to 12 months, a re-evaluation is necessary. 

  9. Bathing: Atopic skin is sensitive and subject to drying. Only specially designed hypoallergenic shampoos should be used on your allergic dog. Rinsing should be thorough. Generally it is best to follow with a hypoallergenic cream rinse or spray to remoisturize the skin after every bath. Virbac's Allermyl® comes as a shampoo or a spray and contains 1-rhamnose, which may reduce itch and inflammation. 

By Carol S. Foil, DVM, MS, Diplomate A.C.V.D.
Board-certified specialist through the American College of Veterinary Dermatology 

Long Term Management of Canine Atopic Dermatitis

The criteria set out by T. Willemse (1986) have been unanimously accepted to establish the diagnosis of canine atopic dermatitis (AD). A revision has been proposed by Prélaud in 1998. As emphasized by C. Griffin (1993), the demonstration of in vivo or in vitro sensitization, is, for many dermatologists, an important criterion for the diagnosis and treatment of AD. This is not the case for man, but if the two diseases have common points, they are not identical.

Treatment of DERMATOSES THAT are related or secondary to atopic dermatitis

According to the phenomenon of summation of effects, several causes of pruritus (allergic and non-allergic) may simultaneously arise in the same animal with a variety of clinical presentations and cause it to rise above its pruritic threshold. Secondary pyoderma is common in canine AD and an adequate treatment regimen may return the animal to a quasi-normal state. Such a case will only be treated in cases of regular reoccurrence and/or if the atopic dermatitis clinical signs become a concern. This reasoning is undoubtedly applicable as well to cases of Malassezia dermatitis. One third of atopic dogs will become sensitive to fleabites in their life and develop flea allergy dermatitis (FAD) and four out of five dogs suffering from FAD are atopic. A well-conducted flea control regimen can eliminate the FAD, and therefore, in certain cases, can enable the animal to fall under its pruritic (i.e., tolerance of pruritic causes) threshold. In such a case, atopic dermatitis treatment is not necessary if the clinical signs are not obvious. If this not the case, the atopic dermatitis should be treated while maintaining absolute antiparasitic treatment. Food intolerance may resemble AD and a food elimination diet is relatively easy to perform.

Specific treatment

Allergenic eviction is “theoretically” the ideal treatment for all cases of allergic dermatitis. Totally avoiding the allergen may enable the animal to fall beneath its pruritic threshold, identical in this instance to the allergic threshold. This avoidance is illusive in the case of pollens. However, it is possible to eliminate environmental feathers and fabrics, and molds can be destroyed by antiseptic or antifungal sprays or even anti-mold paint. However, the role of these allergens in dogs' atopic dermatitis is minimal, and moreover, feathers and fabrics are mostly sources of house dust mite allergen.

Various methods exist to fight against house dust mites, and if necessary, these may be tried around atopic dogs: elimination of furnishing fabrics, carpets, curtains, cushions, etc.; frequent vacuuming with a High Efficiency Particle Air (HEPA) filter vacuum cleaner, which will not release mite particles into the air; use of air dehydration and purification devices; use of acaricide sprays and foggers (some of which contain an Insect Growth Regulator (IGR) and a denaturing agent such as tannic acid which is very efficient for both mite faeces and fungal spores); use of anti-mite mural paints (also anti-insect and anti-mold); use of cushions and covers that can be washed at high temperatures as beds for dogs; and use of protective covers produced for asthmatics (e.g., made of teflon, though these are expensive). An atopic dog which is sensitive to cat dander could, in theory, benefit from cat major allergen avoidance measures (Fel d I) although this allergen is not proven to be recognised by the atopic dog. Because this allergen is transported through the air, it is imperative to take measures against it even if there is no cat living in the house. The measures to be taken are similar to those against mites and also aim at reducing the Fel d I level in cats, which is present in the sebum and is favoured by testosterone secretion, through male castration and frequent baths or shampoos. 

These general measures could therefore be used for atopic dogs and are especially advised if many of them are involved. However, no scientific study has formally proven their usefulness in canine atopic dermatitis.

Hyposensitisation (immunotherapy, desensitisation) has been used in humans, since the beginning of the 20th century, to treat asthma and allergic rhinitis but never in dermatology (although it is also used in cases of hypersensitivity to hymenoptera bites). It first was reported in dogs in the 40s, expanded in North America in the 60s and in Europe in the 1980s. The first explanation for desensitisation efficacy in man was in the production of blocking antibodies (lgG), which combine with allergens before they combine with the IgE. Today, many mechanisms are proposed. In brief, the intervention of other anti IgE anti-bodies (IgG anti IgE, anti-idiotype anti-bodies) has been proposed as well as allergen-specific IgG immune complex, which regulate the immune response. In the same way, acting on Th2-Th1 substitution will lead to a reduction in the IL4 production and an increase in the INF-gamma production. The IL4 offers potential for the IgE synthesis, increases the number of weak affinity IgE receptors or their CD23 soluble form. The INF-gamma inhibits IgE synthesis. Late phase reaction inhibition in desensitized subjects is accompanied by the apparition of T-lymphocytes with a Th1 profile. Finally, desensitization may be accompanied by a cellular and tissue hyposensitisation by reducing the basophilic reactivity, blocking the eosinophilic migration, reducing the neutrophils’ chemotactic activity and abolishing the cytotoxic activity of platelets, among others. These mechanisms can sequentially intervene and differ between the induction and maintenance phases. Halliwell reports IgG and IgE variations in dogs, in both directions, over a two-year period without any clinical correlation. It is reasonable to think that the blocking anti-bodies hypothesis is only a simplification and that no single mechanism can explain the dog's immunotherapy efficacy.

The choice of allergens mainly depends on the in vivo or in vitro test results. Skin tests represent the reference to identify the responsible allergens if they are correctly carried out. The use of biologically standardised allergens, even using human allergy techniques, is preferred. The EIA techniques' serological diagnosis is attractive due to its simplicity. There is a controversy about the reproducibility, and the sensitivity is considered as either weak or very high, but therefore, having a low positive predictive value, which renders the test void. The polyclonal antibodies can have superior values, but if many monoclonal anti-bodies are used grouped, good results can be achieved. Recently, an innovative technique using human specific IgE receptors (FceR1µ) has been proposed. The cellular tests (basophils degranulation test, heterologue passive transfer test) are expensive and require specialized laboratories.

Test results are to be interpreted taking into account the history of the patient and the clinical presentation. Therefore, it must be logical to include allergens in a desensitization protocol (in the case of a positive reaction, danders, molds, pollens, etc., are only used if they are present in the environment). This principle must however be nuanced in the case of cat dander. No standardisation exists for the methods used. Only aqueous extracts are used in North America, whereas in Europe, mainly alum-precipitated extracts are available. It seems that the combination of molds and pollen extracts alters their quality (due to the presence of protease in the mold extracts) and that different types of vials are necessary. 

Desensitization is efficient in man as testified in the results obtained in allergic rhinitis. The hyposensitization results are more or less difficult to evaluate in dogs. In fact, they depend on the animals (age and especially diagnostic criteria), evaluation criteria (telephone follow-up, clinical score), follow-up duration, and recognition or not of “loss of follow-up” as setbacks. Presently, it is considered that 50 to 80% of animals respond to immunotherapy in open studies. T. Willemse demonstrated in 1984, the method's efficacy through a double blind controlled study. The nine-month evaluation seems important: it is usual that improvement at this stage is followed by success.

What are the result variation factors (apart from the diagnostic value and the clinical criteria of each one)?

Allergen identification method: the combination of in vivo and in vitro tests increased success rates, even if it is impossible to confirm the same success rates in the in vitro tests as those obtained after skin-tests.

Allergen specificity: Willemse demonstrated that specific desensitization (based on skin-test results) is significantly more efficient than standard desensitisation (domestic dust, dog and human danders and grass pollens). Kristensen (1994) had better results with specific desensitization in dogs sensitive to Dermatophagoides farinae and/or D. pteronyssinus than with allergens' incorrect choice. 

Allergen nature: Mueller et Bettenay (1996) showed that results were clearly better in dogs sensitive to pollens or Dermatophagoides farinae and pteronyssinus mites than in patients sensitive to molds or insects.

Number of allergens: it does not seem to have any influence.

Breed: no correlation exists between breed predisposition and results. English Setters seem to respond well as opposed to Boxers and West Highland White Terriers.

Age: results are better in the young animal and when the desensitization is carried out at an early stage.

Patient follow-up: Rosser showed in 1996 that results are better in dogs that are closely followed, adapting the injection dosage and frequency according to the tolerance and efficiency.

The use of highly purified allergens could improve results knowing that dogs are becoming sensitized to allergens other than those causing hypersensibility to Dermatophagoides farinae (Der f I and Der f II) and D. pteronyssinus (Der p I and Der p II) in the case of humans. No study has yet proven that the use of corticosteroids during desensitisation would have a very harmful effect on its efficacy. Antibiotic therapy and use of anti-seborrhoeic shampoos do not improve results. Rare cases of secondary effects have been mentioned in an anecdotal manner (urticaria, angiodema, anaphylaxis). An exacerbation of clinical signs is often noticed in the hours following injections. Limited local reactions, which are spontaneously reversible, often appear with alum-precipitated extracts. A majority of veterinary dermatologists believe the efficacy and absence of secondary effects justifies ad vitam eternam hyposensitization. They have empirically noted that the clinical signs reappear in a period of months to years after the treatment has been stopped. 

Symptomatic treatment 

This is useful at the beginning of hyposensitisation (within the first year in successful cases) or on a long-term basis in failed cases (total or partial), or even in cases where treatment was not required (aged animal, owner's hesitation or even, clinically slightly worrying cases apart from a few signs).

Corticosteroids are the most effective medications amongst the symptomatic treatment of allergic dermatitis. They have a powerful anti-inflammatory and anti-pruritic activity. They act at almost all inflammatory and immunological response stages. Their activity, however, varies tremendously. There is no consistency in the individual reaction, not only in relation to the corticosteroid used, but also for the same corticosteroid. The effect is reduced over time and the doses required are increased. They are used topically or systemically. Topical application is of limited value because of the hair (except perhaps as shampoos). Systemic therapy should be limited to the oral administration of prednisolone or methyl-prednisolone (0.5 to 1 mg/kg/day during five to seven days followed by 1 mg/kg every other day, as shortly as possible). Systemic corticosteroids have significant side effects. The most common are polyuria-polydipsia, polyphagia, hepatomegaly, hypothalamo-hypophyso-adrenal axis inhibition, drying of the skin and coat, and alopecia (iatrogenic Cushing’s disease, which is often due to repeated injections of long-acting formulations). Local immunosuppression may give rise to infections (pyoderma), demodicosis, and dermatophytosis. The following rules must be respected regarding the long-term side effects of corticosteroids: use them as little as possible and use the lowest dose possible, preferably every other day and only if alternative anti-pruritic medications have been deemed inefficient.

Various non-steroidal topicals can be used. Anti-seborrhenic shampoos and rehydrating sprays may be used. Some of these contain oatmeal colloidal extracts with an antipruritic action. Recently, a shampoo containing linoleic acid, mono-oligosaccharids, vitamin E (immunomodulatory effects), and piroctone olamine (antiseptic) has been available. Essential fatty acids could reinforce the lipidic barrier role of the epidermis, which is altered in the atopic dog. Due to the probable skin penetration of allergens, a mechanical allergenic elimination effect would therefore be beneficial. Some local use sprays (e.g., containing menthol and hamamelis extracts) may soothe erythematous and excoriated areas. A lotion containing mono-oligo saccharides, vitamin E, linoleic acid, and chitosanide has been put on the market in conjunction with the aforementioned shampoo. Rinses containing pramoxin, a local anaesthetic, could also be helpful.

Some antihistamines that block H1 receptors may be useful; antiH2 are ineffective. Many studies have been performed showing that the most efficient products are clemastine, chlorpheniramine, hydroxyzine, oxatomide and diphenhydramine with approximately 20 to 30% beneficial results. However, only one placebo-controlled, double blind study has been carried out, using astemizole, clemastine and trimeprazine. Moreover, some frequently used products such as cetirizine or ketotifene have not been evaluated at all. Oxatomide also blocks intracellular calcium transport with ketotifene and rupatidine equally blocking other mediators. The relatively low success rates justify successive tests during at least one week at a time, until a satisfactory result is obtained. Trimeprazine, which alone is inefficient, has proven to be able to clearly reduce the need for prednisone. Three studies clearly show a synergic effect between the essential fatty acids and antihistamines. It is therefore possible to control cases having this type of association although they do not respond to any of these treatments.

Essential fatty acids (EFA) have been the subject of many clinical studies. The fatty acids that have been studied are polyunsaturated, administered by oral route, especially omega-3 series eicosapentanoic acid (EPA), and omega-6 series gamma linolenic acid (GLA). These fatty acids compete with the arachidonic acid in the cascade of eicosanoids synthesis where leukotrienes and prostaglandins are formed having an anti-inflammatory activity or at least a pro-inflammatory activity which is much less significant than that observed with the metabolites emitted from arachidonic acid. Various studies have proven their efficacy, including two double blind placebo controlled studies. However, various elements have not yet been made clear: dosage (varying from two to 10 times the advised doses), optimal ratio between omega-3 and omega-6 (between five and 10), the minimal duration of the therapeutic test to predict efficacy (one to 12 weeks), the function of co-factors, the usual diet and its essential fatty acid content, as well as associated therapeutics. The reaction of atopic dogs to fatty acids varies and no supplement or ration exists which suits all dogs; thus, several formulations should be tried, as is done for antihistamines. There are few side effects with EFA (bad breath, diarrhea, with high doses). In practice, they are to be principally used with other anti-pruritic treatments. A dietary approach, based on the quantity of omega-3 and the ratio omega-3/omega-6 may be helpful.

Leukotriene inhibitors have been tried in a few clinical trials. Zileuton, for instance, was not very effective in a placebo-controlled study. Phosphodiesterase inhibitors have shown a moderate efficacy in comparative (arophylline) or double blind, placebo-controlled crossover (pentoxyfilline) studies. Fluoxetine, an anti-depressive agent which inhibits serotonin uptake, and amitriptyline, a tricyclic anti-depressive agent with a antiH1 activity, appears to be moderately efficacious giving good results comparable to the “best” antihistamines (20 to 30 %). Misoprostol, a prostaglandin E analog, has shown interesting effects, including within a blinded placebo controlled study. Cyclosporine is a promising drug for the treatment of canine AD, as in man (administered orally). No significant difference was found in a recent comparative study vs. prednisolone. An injectable formulation of fatty acid copolymers has been shown to be more effective than a combination of antihistamines in a blinded comparative study. Some atopic dogs have bacterial overgrowth and respond to thorough antibiotic treatment regimen, even without visible signs of secondary pyoderma.

Conclusion: combination therapy case management

Each case is different and deserves a “combination therapy,” which associates treatment of complications, eventual allergen eviction measures, symptomatic therapy, and hyposensitisation. It is the key to success.

By Didier-Noël Carlotti, France
Web Site



A combination of Evening Primrose Oil and Anti-histamines provides marked reduction in allergy related skin problems in approximately 75% of itchy pets.

Remember to keep using the Dermcare shampoos as the main cornerstone of your control of allergy related secondary problems.

You will probably have to experiment a bit with the dose and/or type of anti-histamine you use as results vary from pet to pet. Ask your vet for those anti-histamines he/she uses (overseas brands vary from here). 

Evening Primrose oil comes either in capsules or liquid. Ask your vet for the most economical formulation. We use Megaderm (a liquid formulation). It is given by mouth once a day along with the anti-histamine tablets.

Anti-histamine Dose Drowsiness
2 mg/kg 3 times a day Yes
4 mg tablets
4-12 mg/dog twice a day
4 mg/cat twice a day
4 mg tablets
Liquid- 1.2 mg/5mls
0.2 mg/kg twice a day Yes
 60 mg tablets
2 mg/kg twice a day No
10 mg tablets
25 mg tablets
2 mg/kg twice a day Yes

To test the effectiveness, you must continue for at least 35 days. If no improvement, then try a different brand of anti-histamines. 

Balgownie Veterinary Hospital
Web Site

Drugs Commonly Used in the Treatment of Atopic Pets

The following are the common drugs and doses that the Animal Skin and Allergy Clinic uses for the symptomatic treatment of Atopy. 

These doses and schedules are not all strictly adhered to and treatment is designed for individual needs. The doses given below are for guideline purposes only.


  • Polaramine 0.2 - 0.4 mg/kg 2-3 times a day
    Phenergan 2.2 mg/kg 2-3 times a day
    Atarax 2.2 mg/kg 2-3 times a day

Fatty Acids

  • Omega 3 fatty acids
    Evening Primrose Oil


  • Prednisolone 0.5 mg/kg once, twice or three times a week.
    Elocon Ointment thin smear to affected area once a day.

Pulsed Antibiotics

  • Keflex 22 mg/kg 2-3 times a day
    Cephalexin 22 mg/kg 2-3 times a day
    Tylan 10 mg/kg twice a day
    Nizoral 5 mg/kg twice a day


  • Malaseb - used twice weekly initially then weekly long term.
    Pyohex - used twice weekly initially the weekly long term.
    Aloveen - used weekly.


  • Trental



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