Results of allergen-specific immunotherapy in 117 dogs with atopic dermatitis

The success of the treatment of 117 dogs with atopic dermatitis with allergen-specific immunotherapy for up to 48 months was assessed. An excellent response (remission with exclusive immunotherapy) was recorded in 18 of the dogs, a good response (more than 50 per cent reduction in medication and improvement of clinical signs) was recorded in 57, a moderate response was recorded in 24 and a poor response in 18. The mould antigens in the allergen extract were stored in a separate vial before administration and the success rate of the immunotherapy including mould antigens was much higher than in an earlier study in which mould and pollen antigens had been stored in one vial. The success rate was not affected significantly by the age of the dogs when the disease developed, or by their age or the period for which they had shown clinical signs when the treatment began; it was also unaffected by whether pollens, moulds or dust mites were used as antigens, or by whether the offending allergens had been identified by intradermal testing or by serum testing for allergen-specific immunoglobulin E.     

Positive reactions to common allergens in 42 atopic dogs in Japan

Clinically important allergens for the diagnosis and treatment of atopic dermatitis vary geographically. In order to identify the most prevalent allergens in atopic dogs in Japan, 42 dogs with a clinical diagnosis of atopy were tested using both in vivo (intradermal skin test (IDST)) and in vitro (antigen-specific IgE assay) allergy tests. Allergens used for IDST included 26 allergen extracts from eight allergen groups: trees, weeds, grasses, house dust mites (HDM), molds, foods, epithelia, and arthropods. Immunodot assay was used to measure antigen-specific IgE against 24 allergens from these eight groups and against fish such as cod and sole. In the 42 dogs, the most common positive allergen reaction was to HDM on both IDST (29/42 dogs or 69%) and in vitro testing (23/42 or 54.8%). The second most frequent positive allergen reaction was to Japanese cedar pollen (21/42 or 50.0% for IDST and 7/42 or 16.7% for in vitro testing). In both tests, less than 20% of dogs had positive reactions to molds or foods. Positive reactions to cat epithelia were frequently found on IDST, but rarely found on in vitro testing. Agreement between the two tests was found in 26 instances: HDM (21 dogs), Japanese cedar pollen (five dogs) and wheat (one dog). In this study, the two most common allergens involved in atopic dermatitis in dogs in Japan were HDM and Japanese cedar pollen.     

Comparison between IMMUNODOT tests and the intradermal skin test in atopic dogs

This study evaluated a new perspective in the diagnosis of dermatitis in dogs with signs suggestive of allergic skin disease. The results obtained with CMG IMMUNODOT tests using the technique of allergen-specific strip tests, as employed for human allergy diagnosis, were compared with those obtained by the intradermal skin test (IDST). Forty-eight cases completed the diagnostic evaluation, which included IDST, flea-control program, exclusion of sarcoptes and, for some cases, a 1- to 2-month stabilization period on a restricted protein source diet and testing the serum in the presence of allergen-specific IgE and total IgE. The most common disorders included house and storage dust mites, allergic dermatitis and flea-allergic dermatitis together with atopy. This was confirmed serologically. In the case of positive IDST to pollens, Aspergillus spp. and cat epithelium, CMG IMMUNODOT strip tests were negative. A total of 25% of cases were considered to be primarily associated with food hypersensitivity, but only 4% were confirmed serologically. This study emphasizes the value of CMG IMMUNODOT tests as a support in the diagnosis of dog allergy.     

Intradermal skin testing in Icelandic horses in Austria

Icelandic horses in Austria are commonly affected by an allergic inflammatory skin disease recurring during the summer seasons, which shares characteristic features with Culicoides hypersensitivity. However, the causative agents have not yet been identified. Therefore, intradermal skin testing (IDST) with a standardised extract of Culicoides variipennis and 21 other allergens relevant within Austria was performed in 81 Icelandic horses. All horses included into the study were treated regularly with ivermectin and had no history of administration of anti-inflammatory drugs. Forty-three of these horses were affected by summer seasonal recurrent dermatitis (SSRD). No history or signs of any other disease were evident in any horse. Pruritic dermatitis due to ectoparasites, bacteria and dermatophytes were ruled out by means of fungal culture, skin scraping and biopsy. Culicoides variipennis antigens evoked a positive cutaneous reaction in 1 of 38 normal and 3 of 43 SSRD horses at the proposed dilution of 1:50,000 or 1:25,000, and in 24 of 38 normal and 13 of 43 SSRD horses at a dilution of 1:10,000. Furthermore, no significant differences in onset or intensity of skin reactions to the 21 other allergens, including pollens, moulds, mites and insects, except deerfly and horsefly, were obvious between the 2 groups. Efficiency (percentage of correct results) for the used antigens in the skin test was 0.47-0.60. Maximal sensitivity was 0.51. Altogether, 38 of 43 SSRD horses and 28 of 38 normal horses were positive 4 h after allergen administration. The divergence between IDST results and manifestation of clinical signs found in this study underlines the difficulties associated with establishing a skin test protocol in horses within a geographic area. Whether the outcome of this study would have been influenced significantly by using Culicoides spp. present in Austria has to be clarified in future research.     

Correlation of histologic and immunologic findings in cats with miliary dermatitis

Eighteen cats with miliary dermatitis were evaluated, using skin testing and histology. Sixteen cats had allergic skin disease (14 cats had positive skin-test reactions to flea antigen [two of which were also atopic], one was atopic only, and one was allergic to beef). In the two remaining cats, the cause of miliary dermatitis was not identified. Histologically, 17 of the cats had superficial eosinophilic dermatitis and epidermal spongiosis, crusting, and ulceration, which were compatible with an allergic cause. Four of these cats had concurrent eosinophilic plaques, which histologically resembled miliary lesions. This overlap of plaques with miliary lesions indicated that when plaques and miliary dermatitis are found concurrently, both lesions may be caused by the same allergens.     

Cutaneous and ocular adverse reactions in a dog following meloxicam administration

The present report addresses the development of cutaneous and ocular reactions possibly related to meloxicam administration in a dog. Based on clinical signs and absence of laboratory data compatible with the other differential diagnoses considered, the possibility of an adverse drug reaction (ADR) due to meloxicam was considered. Skin biopsy revealed haemorrhage of the superficial and deep dermis, associated with hyperplasia of endothelial cells and epidermal sloughing. Vasculitis in the deep dermis was also noted. Such lesions were considered compatible with an ADR. Although the owner was not aware of any previous allergic reaction to drugs, the animal had a clinical history of atopic dermatitis. Meloxicam is a nonsteroid anti-inflammatory drug (NSAID) in the oxicam family, indicated for the control of inflammation and pain in acute and chronic musculoskeletal disorders in dogs. Although meloxicam is usually well tolerated, the present clinical case represents an alert to practitioners about the potential role of NSAIDS in ADRs in dogs with a history of allergic cutaneous diseases.     

Response to intradermal skin testing with four cat allergen preparations in healthy and allergic dogs

Intradermal skin testing with 4 cat allergens was performed on 40 dogs. The allergens used were a commercial preparation, cat allergen 1, cat pelt extract, and cat serum. Twenty dogs had inhalant allergies (canine atopy) and 20 dogs were healthy. The dogs in these 2 groups were further allotted to groups of dogs with or without exposure to cats. Cat pelt extract was the only allergen that caused a statistically significant (P less than 0.025) difference in the number of positive reactions in healthy vs allergic dogs, with healthy dogs having the greater number of positive reactions. Seven (35%) of the 20 dogs with no known exposure to cats had positive reactions to at least one of the allergens. In dogs that had been exposed to cats, positive reactions developed in twice the number of dogs without clinical signs of canine atopy, compared with those with clinical signs of canine atopy. These data showed that dogs do become sensitized to cat allergen, but that this sensitization may not indicate known exposure to cats or clinical disease.     

Episioplasty for the treatment of perivulvar dermatitis or recurrent urinary tract infections in dogs with excessive perivulvar skin folds: 31 cases (1983-2000).

OBJECTIVE: To evaluate the effectiveness of episioplasty for the treatment of perivulvar dermatitis or chronic or recurrent urinary tract infections (UTI) believed to be secondary to excessive perivulvar skin folds in dogs and to document whether a causal relationship exists between the presence of chronic or recurrent UTI and excessive perivulvar skin folds in female dogs. DESIGN: Retrospective study. ANIMALS: 31 female dogs. PROCEDURE: Medical records of dogs with vulvar dermatitis (group 1; n = 15) or UTI (group 2; 16) were reviewed for history, signalment, physical examination findings, hematologic findings, results of urine or vaginal bacteriologic culture, and results of additional diagnostic procedures. RESULTS: 14 of 15 dogs in group 1 had complete resolution of perivulvar dermatitis and associated clinical signs following episioplasty. One dog had a relapse of clinical signs and vulvar dermatitis 2 years after surgery in association with a 9-kg (1 9.8-1b) weight gain. Sixteen of 16 dogs in group 2 had complete resolution of clinical signs of UTI following episioplasty. Urine samples were obtained via cystocentesis no earlier than 1 month after surgery to confirm resolution of UTI in 13 of 16 of dogs in group 2. Mild-to-moderate incisional swelling was the only surgical complication reported for either group, with the exception of 1 dog in group 2 that had wound dehiscence. All owners were satisfied with surgical outcomes. CONCLUSIONS AND CLINICAL RELEVANCE: All owners reported complete resolution of clinical signs for both groups of dogs. Episioplasty is an effective low morbidity treatment for perivulvar dermatitis and chronic UTI associated with excessive perivulvar skin folds.     

Dermatologic disorders in dogs with diabetes mellitus: 45 cases (1986-2000)

OBJECTIVE: To characterize skin lesions and causative infections in diabetic dogs and evaluate other potential causes of dermatologic disorders, including concurrent endocrinopathies, allergic skin disease, and long-term corticosteroid administration. DESIGN: Retrospective study. ANIMALS: 45 dogs with diabetes mellitus (DM) that were examined by dermatologists. PROCEDURE: Medical records were reviewed for signalment; allergic conditions prior to development of DM; prior corticosteroid administration; and results of dermatologic examinations, ear and skin cytologic examinations, skin scrapings for parasites, bacteriologic and fungal culturing of ear and skin specimens, histologic examinations, and endocrine testing. RESULTS: Bacterial skin infection was the most common dermatologic disorder (n = 38 [84%]), followed by otitis (26 [58%]) and Malassezia-induced dermatitis (19 [42%]). Twenty-two (49%) dogs had pruritic skin disease consistent with allergic dermatitis, which preceded diagnosis of DM. Prior corticosteroid administration was reported in 21 (47%) dogs. Concurrent hyperadrenocorticism was diagnosed in 13 (29%) dogs, and concurrent hypothyroidism was diagnosed in 5 (11%) dogs. Iatrogenic hyperadrenocorticism was diagnosed in 1 additional dog. Only 10 (22%) dogs did not have a documented concurrent endocrinopathy or allergic disease that could have caused the dermatitis. CONCLUSIONS AND CLINICAL RELEVANCE: Bacterial and yeast-induced dermatitis and otitis develop in dogs with DM. Many diabetic dogs with dermatologic problems have a preexisting allergic condition, history of prior corticosteroid administration, or concurrent endocrinopathy that may be a more likely cause of dermatologic problems than DM alone.     

Carpet deodorizer as a contact allergen in a dog

Allergic contact dermatitis was diagnosed in a 7-year-old dog. Clinical signs and history were consistent with a contact allergen being the cause of pruritic skin disease. Patch testing confirmed that carpet deodorizer was the allergen.     

Diagnosis of flea allergy dermatitis: comparison of intradermal testing with flea allergens and a FcepsilonRI alpha-based IgE assay in response to flea control

The objective of this study was to evaluate the accuracy of in vivo and in vitro tests in the diagnosis of flea allergy dermatitis in comparison with history, clinical signs and response to flea control. Intradermal testing using four different sources of flea allergens and FcepsilonRIalpha-based immunoglobulin (Ig)E assays were performed in 15 flea-allergic dogs, 15 atopic dogs and 15 dogs infested with fleas but showing no clinical signs of skin disease. Sensitivity, specificity, negative predictive value, positive predictive value and accuracy were calculated for all five tests and results varied greatly. Sensitivity, specificity and overall accuracy were 27, 83 and 64%, respectively, for one extract (Isotec), 67, 90 and 82% for another extract (Greer), 93, 90 and 91% for flea saliva, 40, 90 and 73% for the recombinant Cte f 1 both produced by Heska Corp. and 87, 53 and 64% for a FcepsilonRIalpha-based IgE assay. These results indicate that intradermal testing with flea extracts is more accurate in the diagnosis of flea allergy dermatitis than in vitro tests. Moreover, pure flea saliva used as a reagent for intradermal testing provided the best results in terms of sensitivity, specificity and overall accuracy although the Greer extract, a whole body flea extract, also allowed a good correlation between intradermal testing results and clinical approach to flea allergy dermatitis diagnosis.     

Immunoglobulin E antibodies to pollens augmented in dogs by virus vaccines

An inbred "atopic dog colony" was established to study the effect of viruses on immunoregulation of immunoglobulin (Ig) E antibodies. Dogs were selected for high skin reactivity to grass and weed pollens. Their offspring were inoculated with pollen extracts in alum immediately after routine vaccinations (attenuated live-virus vaccines for canine distemper and infectious canine hepatitis, and a killed bacterin for Leptospira). Heat labile antipollen IgE antibodies were measured by passive cutaneous anaphylaxis. Pups vaccinated for canine distemper before being given pollen extracts had many more IgE antibodies than did their control littermates who were not vaccinated until after the last pollen extract injection. This may be a natural example of the "allergic break-through phenomenon."     

DNA vaccination against Japanese cedar pollinosis in dogs suppresses type I hypersensitivity by controlling lesional mast cells

Sensitization to allergens of Japanese cedar pollen is known to cause canine atopic dermatitis as approximately 10% of atopic dogs in Japan were positive to the pollen allergen. Among the two major allergens of Japanese cedar pollen, since Cry j 1 is more important than Cry j 2 as an antigen to increase IgE in atopic dogs sensitized to Japanese cedar pollen, Cry j 1 can be a target for immunotherapy. In our study, efficacy of DNA vaccination with a plasmid containing the gene of a major allergen of Japanese cedar (Cryptomeria japnonica, CJ) pollen, Cry j 1, was examined using a dog model experimentally sensitized to CJ pollen allergen. Cry j 1 DNA plasmid and a vector plasmid (pCAGGS) were injected into six dogs and three dogs, respectively, five times with an interval of 1.5 month. After the treatment with Cry j 1 DNA plasmid, production of IgE against Cry j 1 decreased in four of the six dogs in the treatment group, whereas it increased in the three dogs of the control group. The reactivity to the pollen allergen in intradermal testing and provocation testing were obviously reduced in the treatment group, but not in the control group. The number of mast cells in alveolar area of the lung in the treatment group was smaller than that in the control group. Cry j 1 DNA plasmid was also injected into three atopic dogs sensitive to Cry j 1, resulting in improvement of clinical signs in the pollination season. These findings indicated that Cry j 1 DNA plasmid could regulate mast cell-mediated reaction against Cry j 1, which could be an alternative and effective treatment for CJ pollinosis.     

A histamine release assay to identify sensitization to Culicoides allergens in horses with skin hypersensitivity

Skin hypersensitivity is an allergic disease induced in horses by allergens of Culicoides midges. The condition is typically diagnosed by clinical signs and in some horses in combination with allergy testing such as intradermal skin testing or serological allergen-specific IgE determination. Here, we describe an alternative method for allergy testing: a histamine release assay (HRA) that combines the functional aspects of skin testing with the convenience of submitting a blood sample. The assay is based on the principle that crosslinking of allergen-specific IgE bound via high-affinity IgE receptors to the surfaces of mast cells and basophils induces the release of inflammatory mediators. One of these mediators is histamine. The histamine was then detected by a colorimetric enzyme-linked immunosorbent assay. The histamine assay was used to test 33 horses with skin hypersensitivity and 20 clinically healthy control animals for histamine release from their peripheral blood basophils after stimulation with Culicoides allergen extract or monoclonal anti-IgE antibody. An increased histamine release was observed in the horses with skin hypersensitivity compared to the control group after allergen-specific stimulation with Culicoides extract (p=0.023). In contrast, stimulation with anti-IgE induced similar amounts of released histamine in both groups (p=0.46). For further evaluation of the HRA, we prepared a receiver operating-characteristic (ROC) curve and performed a likelihood-ratio analysis for assay interpretation. Our results suggested that the assay is a valuable diagnostic tool to identify sensitization to Culicoides allergens in horses. Because some of the clinically healthy horses also showed sensitization to Culicoides extract, the assay cannot be used to distinguish allergic from non-allergic animals. The observation that sensitization is sometimes detectable in non-affected animals suggested that clinically healthy horses use immune mechanisms to control the reaction to Culicoides allergens that are different or absent in allergic horses.     

Prevalence and features of canine atopic dermatitis in Hungary

Medical records of 600 dogs diagnosed with atopic dermatitis were reviewed and evaluated with reference to history, geographical distribution, breed predilection, clinical signs and positive reactions to allergens as determined by intradermal skin testing (IDT) manufactured by Artuvetrin Laboratories. In 66.6% of dogs, the age of onset of atopic dermatitis was between 4 months and 3 years. Dogs living in the garden suburb of Budapest were more sensitive to house dust mites, fleas and moulds, and dogs from the western part of Hungary were more sensitive to weeds than to other allergens (p < 0.01). Positive reactions were most common to Dermatophagoides farinae followed by human dander. The breed distribution found in the present study was consistent with that reported in the literature, except for the breeds Hungarian Vizsla, Pumi, French bulldog, Doberman Pinscher and Bobtail which were over-represented among atopic dogs compared to the breed distribution of the general dog population of a large city in Hungary. Breeds with verified adverse reaction to food were Cocker spaniels, French bulldogs, Bullmastiffs, Bull terriers, St. Bernards, Tervurens, West Highland White terriers and American Staffordshire terriers (p < 0.05). The clinical signs of atopic dermatitis and their occurrence are in accordance with the data described in the literature.     

A prospective study on canine atopic dermatitis and food-induced allergic dermatitis in Switzerland

Canine atopic dermatitis sensu stricto and food-induced allergic dermatitis are common canine skin conditions, which are often considered clinically undistinguishable. Several attempts have been made to describe populations of atopic dogs and determine breed predisposition but the results were often biased by the use of hospital populations as control group. The present study aims to describe a population of Swiss atopic and food-allergic dogs and to compare it with a data set representing more than 85% of all Swiss dogs. The study, which was carried out during 1 year in several practices and teaching hospital in Switzerland, describes a group of 259 allergic dogs, determines breed predisposition for atopic dermatitis and food-induced allergic dermatitis, compares the clinical signs and features of both conditions, and outlines the clinical picture of five frequently affected breeds.     

Immediate intradermal flea antigen reactivity in clinically normal adult dogs from south Florida, USA

Eighty-six clinically normal adult dogs from southern Florida, USA, with no history of dermatitis, were intradermally skin tested with Greer flea antigen 1:1000 w/v to determine the prevalence of positive immediate intradermal reactivity. This study describes the test group of animals and reports the prevalence of sensitivity to the Greer whole-body flea antigen in normal dogs living in a flea-rich environment. Similar to previous research, the highest prevalence of reactivity to flea antigen occurred at 3–4 years of age. The results indicate that 24% of clinically normal dogs from a flea-rich environment exhibited positive immediate skin test reactivity. These dogs had no clinical signs of flea allergic dermatitis (FAD) in spite of ongoing flea exposure. A 2-year follow-up telephone call to the owners of these flea antigen intradermal skin test (IDST)-positive dogs indicated that only two of 21 dogs had developed clinical signs of FAD.     

Canine atopic dermatitis in Greece: clinical observations and the prevalence of positive intradermal test reactions in 91 spontaneous cases.

Atopic dermatitis was diagnosed in a total of 91 dogs by combining the compatible historical evidence and clinical signs with the presence of one or more positive intradermal test reactions well correlated with the exposure to the aeroallergens and the seasonality of the clinical signs. Compared to the general hospital population Yorkshire terriers, Chinese Shar-Peis and cocker spaniels showed a strong predilection. No such predilection was found regarding the sex of the animals. The age of the dogs at the onset of the clinical signs ranged from 2 months to 8 years (median: 2.5 years). Moderate to severe pruritus, noticed in all the 91 dogs, was either localized (29/91) or generalized (64/91) and non-seasonal (43/91), seasonal (19/91) or of unknown seasonality (29/91). The most common cutaneous lesions included erythema, hyperpigmentation, hypotrichosis and crusts; their body distribution was generalized (64%) or localized (36%) with the feet as the most common site of involvement. Five dogs that had unlesional skin were significantly younger and had been pruritic for a shorter period of time compared to the majority of our study population. Otitis externa (43/91) and bacterial pyoderma (30/91) were the most common conditions associated with atopic dermatitis, while the prevalence of Malassezia dermatitis was very low (2/91). Of the other allergic skin diseases flea allergic dermatitis was the most common (29/91) followed by food hypersensitivity (2 out of the 15 dogs tested). The majority of the dogs demonstrated multiple sensitivities to the 50 aeroallergens tested, while domestic mites (77/91), and particularly Dermatophagoides farinae (64/91), were the most commonly implicated. The total number of the positive intradermal test reactions was increasing parallel to the age of the dogs but it was negatively associated with the presence of skin lesions on the carpal and tarsal joints.     

Resolution of skin lesions and long-term survival in a dog with superficial necrolytic dermatitis and liver cirrhosis

A nine-year-old, neutered female Shetland sheepdog was presented with crusted, ulcerative skin lesions affecting the footpads, commissures of the lips and the lateral canthi of the eyes. Histopathological examination of skin biopsies revealed changes consistent with superficial necrolytic dermatitis and biochemical analysis demonstrated elevated liver enzymes. Abdominal radiography revealed a small liver which, on ultrasonography, appeared diffusely mottled and showed changes suggestive of periportal fibrosis. On exploratory laparotomy, the pancreas appeared normal, but the liver was small and had multiple nodules throughout the parenchyma. This appearance was confirmed as cirrhosis on histopathological examination. The dog was placed on a hepatic support diet and treated with colchicine, essential fatty acid supplementation and raw egg yolks. After four weeks, the skin lesions had resolved and the dog remained free of clinical signs over a 22-month follow-up period.     

A rodent model for allergic dermatitis induced by flea antigens

There have been very few reports of experimentally induced animal models of allergic dermatitis, an immunologic disorder. This report describes the induction of histopathology confirmed allergic dermatitis in C57BL/6 mice along with the consistent clinical sign of alopecia following the administration of flea antigens emulsified in complete Freund's adjuvant (CFA). By comparing different strains of mice, routes of injection, types of adjuvants and different dosages of flea antigens, C57BL/6 mice were found to be most susceptible to flea antigens administered intramuscularly (i.m.) and subsequently developed dermatologic excoriations and local alopecia. The level of specific IgE reactive to flea antigens in C57BL/6 mice after the onset of clinical signs was significantly higher than such levels in mice without clinical signs, suggesting that flea antigen-specific IgE level can be correlated to the severity of allergic hyper-reaction. CD4(+) T lymphocytes and IL-4 rather than IL-10, or IFN-gamma were found to be the predominant cytokines associated with the clinical onset of allergic symptoms in C57BL/6 mice. Further, histopathologic analysis indicated that not only mast cells had infiltrated into the area of the skin lesion, but the damage was found to be at a stage where mast cells were degranulating causing considerable exacerbation of the local injury. In conclusion, this murine allergic dermatitis model induced by flea antigens may provide a useful means to evaluate vaccines or immunodulatory drugs; thus providing researchers with a tool to study allergy-related disorders and other parameters needed in the area of allergic investigations.