Modified rush venom immunotherapy in dogs with Hymenoptera hypersensitivity

BACKGROUND

Hymenoptera envenomation occurs frequently in people and dogs and can trigger anaphylaxis. Venom immunotherapy (VIT) is the only preventive treatment for Hymenoptera hypersensitivity and is indicated for people with severe adverse reactions to insect stings. Rush VIT is an accelerated VIT protocol in people. This has not been reported in dogs.

OBJECTIVES

The objective of the study was to evaluate the safety of modified rush VIT.

ANIMALS

Twenty client-owned dogs with Hymenoptera hypersensitivity based on a history of adverse reactions to Hymenoptera envenomation and a positive intradermal test to honey bee and/or paper wasp venom.

MATERIALS AND METHODS

Dogs received incremental doses of venom via subcutaneous injection one day per week for three consecutive weeks until the maintenance dose was achieved. Vital signs were recorded every 30 min prior to venom administration. Adverse reactions were categorised as localised or grade I-IV systemic reactions.

RESULTS

Nineteen of 20 dogs (95%) completed rush VIT. One dog experienced a grade III systemic adverse reaction and was withdrawn from the study. No adverse reactions occurred in 10 of 20 dogs (50%). Localised and grade I-II systemic reactions occurred in nine of 20 dogs (45%), including nausea (n = 5), injection site pruritus (n = 3) and diarrhoea and lethargy (n = 1).

CONCLUSIONS AND CLINICAL RELEVANCE

Modified rush VIT in dogs was well-tolerated and should be considered for dogs with Hymenoptera hypersensitivity. Larger studies are needed to evaluate the efficacy of VIT in dogs for preventing hypersensitivity reactions to insect stings.

The safety of rush immunotherapy in the management of canine atopic dermatitis-230 cases

BACKGROUND

The duration of the induction phase of allergen-specific immunotherapy conventionally is a period of several weeks, during which the volume of an allergen solution, administered by injection, is gradually increased until the maintenance dose is reached. In rush immunotherapy (RIT), the induction period is abbreviated to achieve a faster improvement in clinical signs of atopic dermatitis (AD) compared to conventional immunotherapy.

OBJECTIVE

The aim of this retrospective study was to evaluate the safety of RIT in 230 dogs with AD and report any adverse effects (AE).

ANIMALS

Two hundred thirty client-owned dogs.

MATERIALS AND METHODS

Medical records of dogs receiving RIT between 2012 and 2021 were analysed and observed AE were investigated. All dogs underwent RIT following a protocol of subcutaneous allergen extract injections, given hourly with an incrementally increasing volume from 0.1 to 1.0 mL.

RESULTS

Adverse effects were documented in 6 of 230 (2.6%) dogs. Five of these dogs (2.2%) showed mild gastrointestinal signs (1 of 5 vomiting, 4 of 5 diarrhoea) and one patient an increase in body temperature by 1.5°C. These occurred at different stages of the RIT protocol. All AE were graded as mild and self-limiting.

CONCLUSIONS AND CLINICAL RELEVANCE

Based on these data, supervised RIT in dogs appears to be a safe procedure to achieve the maintenance dose of allergen immunotherapy earlier with infrequent and mild AE.

Efficacy of short-term combination of intralymphatic allergen immunotherapy and lokivetmab treatment in canine atopic dermatitis: A double-blinded, controlled, randomised study

BACKGROUND

Allergen-specific immunotherapy (ASIT) is an effective therapy for canine atopic dermatitis (cAD). Intralymphatic immunotherapy (ILIT) is potentially beneficial in decreasing time to clinical effectiveness.

OBJECTIVE

To compare clinical efficacy of six monthly ILIT injections combined with three monthly injections of lokivetmab (LVM) with monthly LVM monotherapy at Day (D)168. To monitor dogs treated with ILIT for an additional six months of subcutaneous immunotherapy (SCIT).

ANIMALS

Thirty-six client-owned dogs with cAD.

MATERIALS AND METHODS

In this double-blinded, randomised study, dogs received either six monthly injections of ILIT combined with three monthly LVM injections (ILIT group) or six monthly LVM injections (LVM group). Monthly evaluations with pruritus Visual Analogue Scale (pVAS), Canine Atopic Dermatitis Extent and Severity Index, 4th iteration (CADESI-04) and medication scores (MS) were undertaken. Owners completed a Quality of Life (QoL) questionnaire. Treatment success was predefined as ≥50% reduction in pVAS and CADESI-04 score ≤ 10. After D168, the ILIT group continued with SCIT until subjective assessment at 12 months.

RESULTS

The treatment benchmark at D168 was achieved by 11.1% of the ILIT group and 11.8% of LVM group. A significant decrease in mean pVAS and CADESI scores was observed in both groups (p < 0.001). The ILIT group had a trend towards higher MS compared to LVM. QoL was better in LVM (p = 0.01). At 12 months subjective good-to-excellent response in 77.8% of dogs in the ILIT/SCIT group was seen.

CONCLUSION AND CLINICAL RELEVANCE

The efficacy of this ILIT protocol was comparable with LVM monotherapy at six months. When ILIT was continued with SCIT, a favourable response was seen.

A systematic review of allergen immunotherapy, a successful therapy for canine atopic dermatitis and feline atopic skin syndrome

Canine atopic dermatitis and feline atopic skin syndrome are common presentations in small animal practice. Numerous drugs are used for symptomatic therapy. The only definitive treatment based on the cause of the disease is allergen immunotherapy. Classical allergen immunotherapy (AIT) consists of subcutaneous injections of an extract containing offending allergens, with increasing doses and allergen concentrations at short intervals during the induction phase of several weeks to months followed by a maintenance phase, where a fixed dose is typically given at longer intervals. Dose and interval are tailored to the individual patient. Newer types of AIT include rush immunotherapy, where the induction phase is abbreviated, intralymphatic immunotherapy, and oromucosal or sublingual immunotherapy. AIT aims at inducing a regulatory T-cell response and subsequently downregulating the exaggerated immune response to offending allergens leading to clinical signs. This article reviews the published knowledge about allergen immunotherapy in dogs and cats for small animal practitioners.

Food-specific sublingual immunotherapy is well tolerated and safe in healthy dogs: a blind, randomized, placebo-controlled study

BACKGROUND

Food allergies are increasing in prevalence but no treatment strategies are currently available to cure dogs with food allergy. Over the past decade, experimental food allergen-specific sublingual immunotherapy (FA-SLIT) has emerged as a potential treatment for food allergies in human medicine. However, FA-SLIT has not been investigated in dogs. Therefore, the objective of this study was to prospectively evaluate the safety, tolerability and dispenser sterility of FA-SLIT in healthy dogs before testing it in food allergic dogs. Eight experimental healthy beagle dogs, never orally exposed to peanut, were randomized in two groups to receive SLIT with peanut or placebo for 4 months. Subjects were monitored daily for local and systemic adverse effects. Blood samples for complete blood count and serum biochemistry, and urine for urinalysis were collected and the dogs' body weight was recorded at day 0, 35 and 119 of the SLIT treatment. Sera for the determination of peanut-specific IgG and IgE were collected at day 0, 35, 49, 70, 91, 105 and 119. Intradermal tests were performed before (day 0) and after (day 119) the experiment. The content of each dispenser used to administer treatment or placebo was tested for sterility after usage. In order to assess the presence or absence of sensitization, dogs were challenged 6 months after the end of the study with 2000 μg of peanut extract daily for 7 to 14 days.

RESULTS

All dogs completed the study. The treatment did not provoke either local or systemic side-effects. Peanut-specific IgG significantly increased in treatment group. Even though a significant increase in peanut-specific IgE was also seen, intradermal tests were negative in all dogs before and after the experiment, and the challenge test did not trigger any adverse reactions in the treated dogs, which shows the protocol did not cause sensitization to peanut, but nevertheless primed the immune system as indicated by the humoral immune response. All dispenser solutions were sterile.

CONCLUSIONS

Our results demonstrate that the used peanut-SLIT protocol is well tolerated and safe in healthy dogs. Further studies should evaluate tolerability, safety and efficacy in dogs with food allergy.

Oral glucocorticoids diminish the efficacy of allergen-specific immunotherapy in experimental feline asthma

Allergen-specific rush immunotherapy (RIT) shows promise in treating asthma; however, pet cats will likely require at least initial concurrent glucocorticoids (GCs) to control serious clinical signs. How the immunosuppressive effects of GCs would impact RIT in cats is unknown. The hypothesis of this study was that oral, but not inhaled GCs will diminish the efficacy of RIT in experimental feline asthma. Cats (n=6/group) were sensitized using Bermuda grass allergen (BGA) and randomized to receive BGA-specific RIT for 9 months with an oral GC (prednisolone 10mg daily), inhaled GC (fluticasone 220 μg twice daily), or placebo administered for the first 6 months. Bronchoalveolar lavage fluid (BALF) percent eosinophils and other immunological assays were performed. Eosinophilic airway inflammation was suppressed in all groups at month 6 of RIT (group mean ± SD, 5 ± 2%, 13 ± 4%, and 7 ± 2% for oral GC, inhaled GC, and placebo, respectively; P=0.291). BALF percent eosinophils significantly increased over time only in oral GC/RIT cats between months 6 and 9 (P=0.031). Placebo/RIT cats had significant decreases over time in BGA-specific serum IgE (P=0.031). Concentration of interleukin (IL)-5 in BALF significantly increased over time in inhaled GC/RIT cats (P=0.031). No significant differences were found between groups at month 6 or over time in each group for BGA-specific lymphocyte blastogenesis, percent blood T regulatory cells, or number of IL-10-producing cells. Given the significant increase of airway eosinophilia over time in RIT cats initially treated with an oral GC, inhaled GCs might be better for dampening eosinophilic inflammation until RIT normalizes the dysregulated immune system.

Evaluation of subcutaneous versus mucosal (intranasal) allergen-specific rush immunotherapy in experimental feline asthma

Rush immunotherapy (RIT) is effective for the treatment of experimental feline allergic asthma. In humans, the safety profile of immunotherapy is improved by delivering allergen by a mucosal route. We hypothesized that mucosal (intranasal) RIT would have similar efficacy to subcutaneous RIT with improved safety. Twelve cats sensitized and challenged with Bermuda grass allergen (BGA) were randomized to receive subcutaneous (SC) or intranasal (IN) RIT. Increasing doses of BGA (20-200 microg) were administered over 24h followed by 200 microg BGA weekly as maintenance. Adverse reactions were recorded. Clinical respiratory scores after BGA aerosol challenge, bronchoalveolar lavage fluid (BALF) % eosinophils, and cytokine concentrations were measured before RIT (day 1) and at months 1, 3 and 6 (M1, M3, M6). More adverse events were recorded with SC RIT (n=12) compared with IN RIT (n=6). Respiratory scores were lower by M6 compared with D1 in both the groups. The % BALF eosinophils declined significantly after RIT for both groups (mean+/-SEM, SC RIT D1 62+/-12, M6 9+/-4; IN RIT D1 54+/-9, M6 14+/-6). The BALF IL-4:IFN-gamma ratio significantly decreased over time in the IN RIT group (mean+/-SEM, D1 2.4+/-0.2, M6 1.0+/-0.2). While both protocols decreased eosinophilic airway inflammation, the SC RIT protocol did not cause life-threatening adverse events and demonstrated more consistent resolution of clinical signs after allergen challenge. Either protocol could be considered for the treatment of feline allergic asthma.

Adjuvanted rush immunotherapy using CpG oligodeoxynucleotides in experimental feline allergic asthma

Allergic asthma is driven by relative overexpression of Th2 cell-derived cytokines in response to aeroallergens. In independent studies, both allergen-specific rush immunotherapy (RIT) and CpG oligodeoxynucleotides (ODN) showed promise in blunting eosinophilic inflammation in a model of feline allergic asthma. We hypothesized that RIT using allergen and CpG ODN would work synergistically to dampen the asthmatic phenotype in experimentally asthmatic cats. Twelve cats with asthma induced using Bermuda grass allergen (BGA) were studied. Of these, six were administered adjuvanted BGA RIT using CpG ODN #2142; six were administered placebo (saline) RIT and later crossed over to adjuvanted RIT. Over 2 days, subcutaneous CpG ODN (0.5ng/kg) with BGA (increasing doses every 2h from 20 to 200microg) was administered. Adverse events were recorded and compared with historical controls. Percentage of eosinophils in bronchoalveolar lavage fluid (BALF), % peripheral CD4+CD25+ T regulatory cells (Tregs), lymphocyte proliferation in response to ConA, and cytokine concentrations in BALF were measured over 2 months. Group mean BALF % eosinophils for the adjuvanted RIT cats were significantly lower at week 1 and month 1 (p=0.03 for both), and marginally significantly lower at month 2 (p=0.09) compared with placebo RIT cats. By the end of the study, 8/12 treated cats had BALF % eosinophils within the reference range for healthy cats. Adjuvanted RIT, but not placebo RIT, cats had significant decreases in the ConA stimulation index over time (p=0.05). BALF IL-4 concentrations were significantly higher at week 1 in adjuvanted RIT cats compared with baseline and month 2, and also with placebo RIT cats at week 1. No significant differences were detected between treatments or over time for IL-10 or IFN-gamma concentrations in BALF or for %Tregs cells in peripheral blood. Adjuvanted RIT using CpG ODN in experimental feline asthma dampens eosinophilic airway inflammation. Adverse effects associated with adjuvanted RIT were less severe compared with a historical, non-adjuvanted RIT protocol. The exact mechanism(s) by which adjuvanted RIT alters the aberrant allergic immune response were not elucidated in this study.

Requirement for additional treatment for dogs with atopic dermatitis undergoing allergen-specific immunotherapy

Allergen-specific immunotherapy (ASIT) is one of the main treatments for atopic dermatitis in dogs, but it often requires additional treatments such as antibacterial and antifungal therapy for secondary bacterial and yeast infections, or antipruritic drugs to control the clinical signs or treat the adverse effects of the immunotherapy. Twenty-seven dogs enrolled in a study of ASIT were clinically assessed four times over a period of nine months; their requirement for treatment for secondary bacterial and yeast infections, for the administration of glucocorticoids as additional antipruritic therapy, and for the treatment of any adverse effects of the ASIT were evaluated. Twenty (74 per cent) of the dogs were treated for superficial bacterial pyoderma, 18 (66.6 per cent) required treatment for Malassezia species dermatitis on one or more occasions, eight (29.6 per cent) required treatment for otitis externa due to Malassezia species or bacteria, and eight required glucocorticoids to control their clinical signs. Five (18.5 per cent) of the dogs experienced adverse effects due to the ASIT and two required treatment with antihistamines (H1 receptor antagonists) in order to continue with the ASIT.

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.

Rush immunotherapy in an experimental model of feline allergic asthma

Specific allergen immunotherapy represents the only curative treatment of allergy. No studies have evaluated its efficacy in feline allergic asthma. We hypothesized that an abbreviated course of immunotherapy (rush immunotherapy, RIT) would blunt eosinophilic airways inflammation in experimental feline asthma induced with Bermuda grass allergen (BGA). The 6-month study included asthmatic-RIT treated cats; asthmatic-no RIT treated cats; and non-asthmatic cats. RIT involved increasing parenteral doses (20-200 microg) of BGA over 2 days. Numbers of eosinophils in bronchoalveolar lavage fluid (BALF), serum and BALF immunoglobulins, lymphocyte blastogenesis assays, and cytokines in blood and BALF were evaluated. BALF eosinophils decreased (P=0.048) only in asthmatic-RIT treated cats (baseline 1.1 x 10(6); Month 6, 2.4 x 10(5)). Serum BGA-specific IgG was higher (P<0.001) at all time points after baseline within the asthmatic-RIT group, and was higher (P<0.001) than asthmatic-no RIT cats at Months 1 and 3. No differences (P=0.133) in BGA-specific IgE levels over time were noted among asthmatic-RIT cats, but this group had lower IgE levels (P<0.001) levels than asthmatic no-RIT cats at Months 3 and 6. Differences in BGA-specific IgA levels over time and between the two groups did not reach the traditional level of significance. The mean BGA stimulation index in the asthmatic-RIT cats was biologically insignificant at 6 months, reflecting BGA-specific lymphocyte hypoproliferation. Preliminary results of cytokine profiles were not significantly different; however, BAL cytokine profiles favoring a Th2 response prior to RIT shifted to increased IFN-g and IL-10 thereafter. RIT dampens eosinophilic airways inflammation in cats with experimental asthma. The mechanism of RIT may involve changes in allergen-specific immunoglobulins, induction of hyporesponsive lymphocytes, or alteration of cytokine profiles.

Rush allergen specific immunotherapy protocol in feline atopic dermatitis: a pilot study of four cats

Rush immunotherapy has been shown to be as safe as conventional immunotherapy in canine atopic patients. Rush immunotherapy has not been reported in the feline atopic patient. The purpose of this pilot study was to determine a safe protocol for rush immunotherapy in feline atopic patients. Four atopic cats diagnosed by history, physical examination and exclusion of appropriate differential diagnoses were included in the study. Allergens were identified via liquid phase immunoenzymatic testing (VARL: Veterinary Allergy Reference Labs, Pasadena, CA). Cats were premedicated with 1.5 mg triamcinolone orally 24 and 2 h prior to first injection and 10 mg hydroxyzine PO 24, 12 and 2 h prior to first injection. An intravenous catheter was placed prior to first injection. Allergen extracts (Greer Laboratories, Lenoir, North Carolina) were all administered subcutaneously at increasing protein nitrogen units (pnu) every 30 minutes for 5 h to maintenance dose of 15,000 pnus ml-1. Vital signs were assessed every 15 minutes. Two cats developed mild pruritus and the subsequent injection was delayed 30 minutes. No changes in either cat's vital signs were noted, nor was there any further pruritus. All four cats successfully completed rush immunotherapy. Two cats developed a dermal swelling on the dorsal neck one week later. In these four cats, this protocol appeared to be a safe regimen to reach maintenance therapy. A larger sample of feline patients is needed to determine the incidence of adverse reactions and to follow the success of ASIT based upon this method of induction.

Effectiveness of low dose immunotherapy in the treatment of canine atopic dermatitis: a prospective, double-blinded, clinical study

There are anecdotal reports of increased effectiveness of allergen-specific immunotherapy (ASIT) in dogs with doses of vaccine lower than that recommended by the manufacturers. However, no controlled studies have been carried out. The aim of this prospective, double-blinded study was to evaluate whether induction and maintenance with low dose (LD) ASIT resulted in a different success rate compared with the standard dose (SD). Twenty-seven dogs with confirmed atopic dermatitis were allocated by block randomization to two groups. One group (n = 13) received SD ASIT; the other group (n = 14) received LD ASIT (1/10 of the SD) following the same frequency protocol. Cases were graded at 0, 3, 6 and 9 months for clinical signs using a modified canine atopic dermatitis extent and severity index (mCADESI) and for pruritus using a 0-5 descriptor scale. There were no significant differences between the groups in the pruritus and mCADESI scores (P > 0.155) at the end of the study, and the changes in pruritus (P > 0.920) and mCADESI (P > 0.296) scores from the beginning to the end of the study were similar in both groups. Pruritus scores in both groups did not change during the study (P > 0.052). However, significant reductions in mCADESI scores were seen in both groups (P < 0.032). Six dogs achieved a final pruritus score of 0, six achieved a reduction in pruritus score and 15 did not improve or worsened. There was, therefore, no evidence that LD ASIT is more effective than the standard protocol.

Use of immunostimulatory liposome-nucleic acid complexes in allergen-specific immunotherapy of dogs with refractory atopic dermatitis - a pilot study

This pilot study evaluated the effects of immunostimulatory liposome-plasmid-DNA complexes combined with specific allergens for immunotherapy of refractory canine atopic dermatitis. Seven dogs with previously diagnosed atopic dermatitis and unsatisfactory response to at least 12 months of conventional allergen-specific immunotherapy underwent a series of six intradermal injections (weeks 0, 2, 4, 6, 10 and 14), with patient-specific allergen extracts contained in cationic liposome-DNA complexes. Degree of pruritus was assessed on a visual analogue scale. Lesion scores were determined using the Canine Atopic Dermatitis Extent and Severity Index (CADESI) and medication usage was recorded at weeks 0 and 14. Canine cytokine mRNA expression in peripheral blood mononuclear cells collected prior to treatment and at the completion of the study was determined for IFN-gamma, IL-4, TNF and IL-10 genes using quantitative reverse transcription competitive polymerase chain reaction. Repeated intradermal injections of specific allergens incorporated into liposome-nucleic acid complexes were well tolerated in all seven dogs. There was a significant improvement in pruritus scores (P = 0.0277) and concurrent significant decrease in IL-4 production (P = 0.0428) at the completion of the trial compared to pretreatment values. Medication scores, CADESI and production of other cytokines did not change significantly with treatment. These early results suggest that antigen-specific immunotherapy using a novel liposome-nucleic acid complex vaccine may be beneficial for treatment of established atopic dermatitis in dogs using lower antigen doses. Further investigations in larger numbers of dogs with earlier stages of disease are warranted.

Allergen-specific immunotherapy induces Th1 shift in dogs with atopic dermatitis

Allergen-specific immunotherapy has been applied to canine atopic dermatitis. Despite the accumulated clinical evidence of its effect for atopic dogs, the basic immunologic mechanisms were not fully understood. In this study, the cytokine profile ex vivo in canine atopic dermatitis before and after allergen-specific immunotherapy was characterized using competitive reverse transcription-polymerase chain reaction (RT-PCR). Blood samples were collected from 10 dogs with atopic dermatitis and peripheral blood mononuclear cells were stimulated with house dust mite antigen. The levels of IFN-gamma and IL-4 mRNA were lower in atopic dogs compared with non-atopic controls. The ratio of IFN-gamma/IL-4 was low in atopic dogs indicating a cytokine profile polarized to Th2. The level of IFN-gamma after immunotherapy was significantly higher than that before (P < 0.05) whereas that of IL-4 mRNA was not changed. Consequently, the ratio of IFN-gamma/IL-4 after immunotherapy was significantly higher than that before immunotherapy (P < 0.05). These results indicate a Th2 cytokine bias is the dominant state in atopic dogs and allergen-specific immunotherapy causes a shift to wards a Th1 bias by enhancing IFN-gamma expression.

A retrospective study of hyposensitization in canine atopy based on a polyclonal ELISA test

Compliance with the treatment protocol and the most significant reasons encountered in general practice for the discontinuation of treatment in hyposensitized dogs are examined. The data are based on (1) a review of order forms for the hyposenzitization mixture and information sheets for an ELISA test and (2) telephone interviews with dog owners. Most of the owners (81%) gave their dogs allergen injections at home. Non-compliance was defined as discontinuation of treatment in the induction period; 33.9% of the owners became non-compliant. A large proportion of non-compliant owners (51.2%) claimed to be unaware of the length of the induction period. Furthermore, 70.2% of the owners were not aware that treatment would most likely need to be lifelong if it was to remain effective. Although 67.5% of the owners perceived that their dogs had beneficial effects from hyposensitization, only 36.3% of the dogs were receiving maintenance injections at the time of the telephone interview, considerably reducing the long-term benefit from treatment. Canine atopy is a chronic disease characterized by remission and relapses. Since no control group was available in this study, the beneficial outcome of treatment reported by the owners could be partly due to the natural course of the disease. Nevertheless, the results indicated that the long-term effect of hyposensitization in canine atopy will be reduced by premature discontinuation of treatment in the maintenance period. The discontinuation of treatment could be a reflection of the treatment becoming less effective, owing to the development of new hypersensitivities or to a reduction in the placebo effect that may occur in 'new' treatments. However, poor client education and follow-up seem to be important reasons for both noncompliance and discontinuation of the treatment in the maintenance period.

Canine atopic dermatitis: a retrospective study of 169 cases examined at the University of California, Davis, 1992-1998. Part II. Response to hyposensitization

One hundred and sixty-nine dogs were diagnosed with atopic dermatitis, and treated with hyposensitization for at least 1 year based on the results of either intradermal skin tests (IDST) or enzyme-linked immunosorbant serum assays (ELISA). Excellent (i.e. hyposensitization alone controlled clinical signs), good (> 50% improvement), moderate (< 50% improvement) and no (clinical signs were unchanged) responses were seen in 19.5, 32.5, 20.1 and 27.8%, respectively. Age of onset, age when treatment was initiated or the duration of clinical signs had no influence on response to hyposensitization. Dogs having concurrent flea allergy dermatitis were statistically more likely to respond better than dogs with concurrent food allergies. Although not statistically significant, there were trends for Golden Retriever and male dogs to respond better than other breeds and female dogs, respectively. Dogs having more than 21 positive reactions in allergy tests and treated with more than 21 allergens had lower response scores, and a longer time course before achieving beneficial response. Lower response scores were seen in dogs having positive reactions to cultivated plants, grasses, trees or insects. There was no difference in response to hyposensitization whether based on IDST or ELISA results.

The ACVD task force on canine atopic dermatitis (XXIV): allergen-specific immunotherapy

Allergen-specific immunotherapy (ASIT) has been used for years to treat dogs with atopic dermatitis (AD) and humans with atopic diseases. The efficacy of ASIT has been well documented for humans with respiratory atopic diseases and stinging insect allergy, but its effectiveness seems more controversial for patients with AD. In spite of insufficient evidence derived from randomized controlled trials, multiple open studies and a large body of clinical observations suggest that ASIT is effective in controlling the clinical signs of dogs with AD. As a result of the scarcity of evidence from controlled trials, the true efficacy of ASIT, and the optimal protocols for allergen dose and frequency of injection are currently unknown. Allergen-specific immunotherapy nevertheless may be included in the treatment of canine AD because of its potential advantages and limited disadvantages compared to other forms of therapy. There is no evidence, however, for the preference of any specific treatment protocol. The predictive value of historical, clinical and immunologic features related to the efficacy of ASIT in dogs with AD are discussed in this paper. Adverse reactions, and the requirements for monitoring of patients receiving ASIT, then are reviewed and detailed. Finally, this review highlights aspects of ASIT where further research and controlled studies are needed.

Feline atopy in three littermates

This case report describes the history, clinical signs and diagnosis of a pruritic skin disease in three sibling cats living the same household. Clinical signs consistent with pruritus (i.e. hair pulling, hair loss, excessive grooming and face rubbing) were first noted when the cats were 6 months of age. The cats were treated for a possible ear mite and/or flea infestation; there was no response to treatment and clinical signs progressed. Although the presence of pruritus in a multiple cat household suggested an infectious or contagious aetiology, none could be identified. There was no improvement in clinical signs after a 60-day flea control trial, three treatments of ivermectin, an 8-week restricted diet or removal from the home for 10 days. A diagnosis of feline atopy was made on the basis of elimination of other causes of pruritus, consistent history and clinical signs, a positive intradermal skin test and response to therapy.

Evaluation of the safety of an abbreviated course of injections of allergen extracts (rush immunotherapy) for the treatment of dogs with atopic dermatitis

OBJECTIVE

To evaluate the safety of an abbreviated course of injections of allergen extracts (rush immunotherapy) for the treatment of dogs with atopic dermatitis.

ANIMALS

30 dogs with atopic dermatitis examined at a veterinary dermatology referral practice for treatment with allergen-specific immunotherapy.

PROCEDURE

A catheter was placed in a vein in each dog. Dogs were constantly observed throughout the procedure. Allergen extracts were administered in increasing concentrations every 30 minutes for 6 hours to a maintenance concentration of 20,000 protein nitrogen units/ml. Epinephrine, oxygen, and emergency treatment were available as needed.

RESULTS

In 22 (73%) dogs, rush immunotherapy safely replaced the prolonged induction period (15 weeks) of weekly injections that consists of increasing concentrations of allergen extract. In 7 (23%) dogs, the induction period was abbreviated to 4 weeks. Of the 8 dogs that developed problems during rush immunotherapy, increased pruritus necessitated premature cessation of rush immunotherapy in 7, and 1 developed generalized wheals. Oral administration of prednisolone (1 mg/kg of body weight) resulted in resolution of adverse effects in all 8 dogs.

CONCLUSION AND CLINICAL RELEVANCE

Rush immunotherapy performed by personnel at a veterinary hospital is a safe method for treatment of dogs with atopic dermatitis.

Advances in the diagnosis and treatment of atopy

Regarding the diagnosis of atopy, the emphasis in this article has been on how to use the initial history and physical examination findings to lead the clinician towards this diagnosis. After a systematic approach to the differential diagnosis of pruritus in the dog has been completed, the diagnosis of atopy can be further evaluated using one of the specific allergy tests available. The author's preference is the IDST to aid in the confirmation of the presence of atopy. Regarding the treatment of atopy, the emphasis in this article has been on the use of immunotherapy as the specific treatment for this disease. Careful monitoring of dogs on immunotherapy is essential to obtain optimum results, and response rates to treatment may be significantly improved by implementing various modifications in the standard hyposensitization protocol being used by the clinician.

Insect and arachnid hypersensitivity

Insect hypersensitivity reactions can have a large number of clinical presentations. The majority of reactions are pruritic and involve the short- or sparsely haired areas of the body. Most are associated with eosinophilic infiltration into the skin, often in a perivascular pattern. The diagnosis may be based on compatible clinical signs and improvement with aggressive insect control and, in some cases, confirmation via provocative exposure. Intradermal, prick, or serum testing for allergen-specific IgE can be used to document the presence of reaginic antibodies against insect allergens. Treatments include avoidance, aggressive insect control, and symptomatic support; in some cases, immunotherapy may be useful in decreasing the severity of clinical reactions to insects.

Treatment of bilateral nasal polyposis and chronic refractory inhalant allergic rhinitis in a chimpanzee (Pan troglodytes)

Over a 15-yr time span, a 30-yr-old female chimpanzee (Pan troglodytes) exhibited recurrent upper respiratory disease that was suspected to be allergen induced. Until 1993, symptomatic therapy with several different antibiotics and antihistamines yielded variable results. In early 1993, the chimpanzee was consistently observed to be open-mouth breathing despite medication. Nasal polyposis was diagnosed using rigid endoscopy in September 1993, and the polyps were removed by loop excision. A fluorescent allergosorbent test was performed to differentiate hypersensitivity to specific regional allergens causing chronic inhalant allergic rhinitis. Oral immunotherapy was then instituted using standard human treatment for Sacramento Valley pollens. This combination of polyp removal and immunotherapy resulted in a marked reduction of clinical signs, and continuous oral immunotherapy has controlled these signs. Hyposensitization therapy will continue for at least 2-3 yr. The chimpanzee continues to breath normally following occasional antihistamine treatment.

Efficacy of hyposensitization in feline allergic diseases based upon results of in vitro testing for allergen-specific immunoglobulin E

A survey was undertaken to evaluate the responses to hyposensitization in cats for which a diagnosis of allergic disease was made by assessment of clinical signs and evaluation of allergen-specific immunoglobulin E (IgE) using the radioallergosorbent test (RAST). Eighty-one cases were available for analysis. In 39 cases, a dietary change resulted in some subjective improvement, which usually was minimal; however, some cases had significant improvement. In 75.3% of cases, an improvement of at least 50% was noted and ascribed to a combination of immunotherapy and dietary change, when implemented. The response of the 42 cases in which immunotherapy alone was used or where there was no response to dietary change was broadly similar. Response of the specific dermatological conditions ranged from 93.6% in the case of linear granuloma to 60% in cases where self-induced hair loss was evident. Response also was good in cases of presumed allergic asthma (86.1% improvement) and suspected allergic otitis externa (62.6% improvement). In nine patients, the hyposensitization was discontinued due to lack of response. The results suggest that confirmation of a suspected diagnosis of allergic disease in cats by means of in vitro tests and subsequent therapy with hyposensitization should be a major consideration in feline practice.

[Atopic dermatitis in dogs: therapeutic possibilities]

The possibilities of treatment in canine atopy are discussed. Depending on the age of the dog, the duration and seasonal pattern of disease, and the number of causative allergens, withdrawal therapy, administration of glucosteroids or hyposensitisation may be chosen.

Endotoxic shock. Part II: A review of treatment

Treatment of endotoxemia is difficult because of the numerous mediators involved in the body's response to endotoxin. There are three possible approaches in treating endotoxemia. The interaction of endotoxin with target cells can be blocked by inducing tolerance, decreasing plasma endotoxin concentrations, or interfering with endotoxin binding. Once endotoxin has interacted with target cells, endogenous mediators can be blocked with a huge variety of drugs. The effects of corticosteroids, cyclooxygenase blockers, leukotriene blockers, platelet activating factor blockers, tumor necrosis factor blockers, oxygen radical scavengers, opiate antagonists, antihistamines, calcium channel blockers are detailed. Supportive care of the endotoxemic patient continues to be a critical aspect of treatment. Controversies regarding solutions to use for volume support, vasoactive and cardiostimulant drugs, metabolic support, and treatment of disseminated intravascular coagulation are reviewed.

Specific immunotherapy in the treatment of Culicoides hypersensitive horses: a double-blind study

Fourteen privately owned horses completed a six month, controlled, double-blind trial to assess the efficacy of immunotherapy using an aqueous extract of whole, unfed Culicoides variipennis in the treatment of Culicoides hypersensitivity. Selected horses had a history of a seasonal, pruritic dermatitis, clinical signs and distribution compatible with Culicoides hypersensitivity, failed to improve in response to ivermectin therapy, and reacted to several dilutions of Culicoides extracts without significant reactivity to other possible allergens including insects, moulds and feeds. One horse from the control group (n = 8) and one from the test group (n = 6) improved. Statistically, there was no significant difference between horses on Culicoides antigen and control horses. In each group, four owners thought that their horses had improved.

Allergic inhalant dermatitis attributable to marijuana exposure in a dog

Exposure to marijuana was believed to be responsible for clinical signs consistent with allergic inhalant dermatitis in a dog. The dog had facial and pedal pruritus associated with bilateral ocular discharge. Clinical signs resolved when the dog was kenneled, but returned when the dog was returned to its home. The results of intradermal skin testing, using a standard tray of 51 inhalant extracts, did not adequately account for the dog's clinical signs. Later, the owners indicated that previous residents of the owners' home had cultivated marijuana intensively inside and outside of the home. Intradermal skin testing with a source of marijuana pollen extract was performed, yielding a positive reaction in the dog and a negative reaction in another dog without clinical or historical evidence of allergic inhalant dermatitis. The affected dog was treated successfully and exclusively by hyposensitization with marijuana pollen extract.

Survey of intradermal skin testing practices in North America

Allergic skin diseases are commonly diagnosed by veterinarians. Inhalant-related allergic diseases are especially prevalent in companion animal species. Intradermal skin testing (IDST) is the usual method for diagnosis of these syndromes, and is often followed by hyposensitization treatment if an animal reacts to substances during testing. A mail survey of veterinarians in the United States and Canada was conducted to determine current procedures in use for IDST and opinions on results of IDST and hyposensitization. Results of the survey indicate that IDST procedures are not currently standardized and that there is wide variation in the methods used. Opinion regarding results of skin testing and hyposensitization was largely in agreement with previously published patient studies.

Effect of immunotherapy on the serum concentrations of allergen-specific IgG antibodies in dog sera

An ELISA assay which uses horseradish peroxidase conjugated anti-canine IgG and polystyrene microtiter wells for detection of allergen-specific IgG in the serum of dogs is described. Individual allergen blanks were used to account for the variable nonspecific binding among various allergens, and the results observed in milliunits of absorbance were normalized using four reference sera. The coefficients of variation for the intraassay and interassay variability ranged from 1.34 to 12.50% and 4.62 to 9.77%, respectively. The relationship between ELISA results and serum concentrations of allergen-specific IgG was quantified. IgG antibodies with specificity for various allergens were found in the majority of non-atopic individuals and in all atopic subjects. Specific immunotherapy resulted in a rise in the serum concentration of allergen-specific IgG.

[Atopic dermatitis in dogs: therapeutic possibilities]

The possibilities of treatment in canine atopy are discussed. Varying with the age of the dog, the duration and seasonal pattern of the disease, and the number of causative allergens, withdrawal therapy, administration of glucocorticosteroids or hyposensitisation may be chosen.

Double-blind flea hyposensitization trial in cats

In a double-blind clinical trial, flea antigen was injected subcutaneously or intradermally in cats with signs of fleabite allergic dermatitis. No significant clinical improvement was noted by the investigator or the owner in either antigen-treated or control groups over a 20-week period.

Effect of hyposensitization on atopic dermatitis in dogs

In a double-blind study, 51 dogs with clinically defined atopic dermatitis were injected with either alum-precipitated allergen solutions or a placebo. Comparing the treatment results of both groups on the basis of scores for clinical signs, a significant difference in clinical improvement was established in favor of the allergen-treated dogs (P less than 0.01). The proportional changes of scores for clinical signs in the allergen-treated group ranged between +27.3% and -100% (median, -61.5%) and in the placebo group between +36.4% and -100% (median, 0.0%) with respect to the initial scores. Immediate skin test reactivity disappeared only in the dogs with a good clinical response. Of 27 dogs treated with an allergen solution, 16 (59.3%) had an improvement of 51% or more. In the placebo group, 5 of 24 dogs (20.8%) reacted this way. There was total remission of the clinical signs in 9 and 4 dogs, respectively. In the dogs in which, after 9 months of hyposensitization, any improvement was observed, the chance for final improvement of more than 51% was calculated as 84%. Discriminant analysis revealed that evaluation of the effect of immunotherapy can be restricted to the 9-month follow-up examination.