Advances in methodology for diagnosis of allergic skin disease

Advantages of IDST for diagnosis of atopy and selection of antigens for hyposensitization include the following: 1. The test is widely accepted by clients. 2. The clinician can select individual test allergens based on the patient history and geographic location. 3. It has been the standard for diagnosing atopy in the dog for more than 40 years. Disadvantages of IDST include the following: 1. The test should be performed on a regular basis to maintain reliability. 2. Interpretation of test results is subjective. 3. The test is not standardized on the basis of the examiner, source of the allergen, or reproducibility. 4. There is occasional difficulty in performing the test (e.g., need for sedation). 5. Anaphylaxis is a potential risk. 6. A significant amount of office time is needed to perform the test. 7. Condition of the patient's skin (e.g., lichenification, hyperpigmentation, pyoderma) may preclude its use. 8. There is a possibility of failure to test for appropriate allergens. 9. There may be false-positive and false-negative reactions. 10. Other medications can interfere with the test (e.g., antihistamines, corticosteroids). Advantages of in vitro testing for diagnosis of atopy and selecting antigens for hyposensitization include the following.(ABSTRACT TRUNCATED AT 250 WORDS)     

Atopy in pet animals

The pathomechanism of canine and feline atopy has not been totally defined. Immunotherapy has been shown to be effective. The diagnosis of canine and feline atopy is still fraught with complications. Several new drugs may be useful in the treatment of canine and feline atopy.     

Treating canine atopic dermatitis with unsaturated fatty acids: the role of mast cells and potential mechanisms of action

Canine atopic dermatitis (CAD) is an inflammatory skin disorder that is characterized by pruritus and associated cutaneous changes. Treatment interventions include allergen avoidance, allergen‐specific immunotherapy as well as a symptomatic therapy using glucocorticoids and antihistamines. In addition, a dietary intervention using polyunsaturated fatty acids (PUFA) has been shown to alleviate symptoms in some dogs. Although the beneficial effects of PUFA in the treatment of CAD have been known for several years, their mode of action remains unclear. This review discusses the evidential basis of the therapeutic use of dietary PUFA in the treatment of CAD. Particular emphasis will be placed on the role of cutaneous mast cells. In addition, recent evidence from in vitro studies on the regulation of mast cell exocytosis will be used to build a mechanistic model of the active principle of PUFA. It is proposed that dietary PUFA are integrated into mast cell membranes resulting in a reorganization of membrane microdomains. This may then be accompanied by functional changes of membrane‐associated proteins such as the phospholipases D (PLD), enzymes having an important impact on mast cell exocytosis processes.     

Feline immunotherapy

Feline allergen specific immunotherapy (ASIT) is considered to be a safe and effective treatment for feline atopy. ASIT is defined as the practice of administering gradually increasing quantities of an allergen extract to an allergic subject. The purpose of which is to reduce or eliminate the symptoms associated with subsequent exposures to the causative allergen. ASIT offers an effective and safe treatment option for cats. Reported success rates range for 60 to 78% in feline atopic patients. Additionally, the reported incidence of side effects in feline atopic patients undergoing ASIT is very low and mainly anecdotal.     

Comparison between an intradermal skin test and allergen-specific IgE-ELISA for canine atopic dermatitis

The aim of this study was to compare the results of an intradermal skin test (IDST) with those of an allergen-specific IgE-ELISA in 210 dogs with atopic dermatitis. All the dogs had a clinical diagnosis of atopic dermatitis and underwent an IDST. The sera of all dogs were analysed for allergen-specific IgE by ELISA using the monoclonal antibody D9 against dog IgE. IDST was used as the standard assay. In both methods, the following antigens provided a positive test result: Dermatophagoides farinae, Acarus siro, Tyrophagus putrescentiae, ragweed, mugwort and Lepidoglyphus destructor. ELISA had an overall sensitivity of 82.4% and an overall specificity of 93.8%. The overall accuracy of the ELISA was 91.3%. The evaluated monoclonal D9 ELISA was found to be a reliable tool for the diagnosis of those allergens that cause clinical atopy, and can be recommended for use in dogs when immunotherapy is a therapeutic option.     

Probable hypersensitivity vasculitis in a dog

Allergy immunotherapy (hyposensitization) injections or ibuprofen were implicated as causes of hypersensitivity vasculitis in a dog suffering from probable food allergy. The vasculitis was associated with increased complement component, C3, and resulted in deep, ulcerated draining nodules and plaques on the forelimbs, lateral aspects of the thorax, and thighs. Injections had been given as immunotherapy for suspected atopy. Vasculitis, associated with allergy immunotherapy and increased complement component, C3, as well as with nonsteroidal anti-inflammatory drugs, has been reported in human beings.     

Principles of treatment for vaccine-associated sarcomas

In the last decade, there has been a great deal of information surrounding the etiology, diagnosis, and treatment of feline vaccine-associated sarcomas. The presence of a mass in areas used for subcutaneous or intramuscular injections should alert the clinician to the possibility of a vaccine-associated sarcoma. Early detection and subsequent treatment is paramount to limit local invasion and distant metastasis. The current data are suggesting that a team approach with multi-modality therapy is the appropriate way to address this disease. In the following article, we will discuss the history/incidence, pathology, diagnosis, and current treatment options, which include a combination of surgery, radiation, and chemotherapy for vaccine-associated sarcomas.     

Cytology in food animal practice.

Diagnostic cytology can greatly aid the clinician in determining a more refined diagnosis, prognosis, and treatment plan to serve the client and patient better. Sample collection is not difficult and can be done in the field as well as in a hospital setting. The collection and sample handling procedures described in this article can help the clinician to obtain diagnostically valuable samples. In many cases, preliminary cytologic evaluation can be performed by the general practitioner. Additional diagnostic evaluation and interpretation are readily available from trained pathologists at diagnostic laboratories.     

FC‐36 The use of immunostimulatory bacterial DNA sequences in allergen‐specific immunotherapy of canine atopic dermatitis

The purpose of this study was to evaluate a combination of immunostimulatory bacterial DNA sequences and allergen‐specific immunotherapy for the treatment of canine atopic dermatitis. Seven dogs with nonseasonal atopic dermatitis diagnosed by history, clinical signs and exclusion of differential diagnoses were included. All dogs had been on allergen‐specific immunotherapy for at least 12 months with incomplete responses, were on additional antipruritic therapy and showed residual pruritus. Pruritus was marked by the owner on a visual analogue scale, lesions were determined by a clinician using the Canine Atopic Dermatitis Extent and Severity Index (CADESI), and concurrent medications were recorded before entering the study and after 14 weeks of treatment. Peripheral blood mononuclear cells were isolated and cultured; canine cytokine message for IFNγ, IL‐4, TNF and IL‐10 was quantitated using RT‐PCR. A mixture of allergen extract and liposome‐DNA complexes was injected intradermally at the beginning of the study and after 2, 4, 6, 10 and 14 weeks. CADESI, pruritus and medication scores, and cytokine messages at the beginning and end of the study were compared with a paired t‐test. There were significant improvements in pruritus scores (P = 0.0277). Reductions in medication scores and CADESI were not statistically significant. IL‐4 production decreased significantly (P = 0.0428); decreases in other cytokines were not significant. Although the number of dogs in this pilot study was small, the results warrant further investigation of a combination of immunostimulatory bacterial DNA sequences and allergen‐specific immunotherapy for the treatment of canine atopic dermatitis. Funding: Self‐funded.     

Critical care monitoring.

Small mammals and birds present unique challenges for the clinician in treatment of life-threatening conditions. Numerous books have been written on shock, critical care, and cardiopulmonary resuscitation in small animals. The basic protocols can be adapted for use in small mammals and birds. A general review of the pathophysiology of shock is important to the understanding of fluid therapy plans discussed in this article. Using the general principles of cardiopulmonary-cerebral resuscitation in small animals, protocols are discussed for use in birds and small mammals.     

Shock and cardiopulmonary-cerebral resuscitation in small mammals and birds.

Small mammals and birds present unique challenges for the clinician in treatment of life-threatening conditions. Numerous books have been written on shock, critical care, and cardiopulmonary resuscitation in small animals. The basic protocols can be adapted for use in small mammals and birds. A general review of the pathophysiology of shock is important to the understanding of fluid therapy plans discussed in this article. Using the general principles of cardiopulmonary-cerebral resuscitation in small animals, protocols are discussed for use in birds and small mammals.     

The future of immunotherapy for canine atopic dermatitis: a review

Allergen specific immunotherapy (ASIT) is a foundation treatment for canine atopic dermatitis (CAD), though few critical studies have documented its effectiveness as a disease‐modifying treatment in dogs. The mechanisms by which ASIT works in dogs have not been elucidated, although they are likely to parallel those known for humans. Current ASIT approaches in CAD focus on either subcutaneous or sublingual administration. Greater knowledge of major allergens in dogs, ideal dosage regimes and details of allergen admixture are likely to lead to better efficacy in CAD. Evaluation of biomarkers for successful therapy may also be of benefit. Potentially important advances in human medicine, that have yet to be explored in dogs, include use of modified allergen preparations such as allergoids, recombinant major allergens or allergen peptides; modification with adjuvants; or packaging of the above in virus‐like particles. Co‐administration of immunomodulators such as CpG oligodeoxynucleotides or specific monoclonal antibodies might direct the immune response in the desired direction while calming the “cytokine storm” of active disease. Initial trials of alternative routes of administration such as intralymphatic immunotherapy have yielded exciting results in humans, and continuing study in dogs is underway. Progress in ASIT of human food allergy may provide clues that will assist with improved diagnosis and patient management of CAD. Importantly, further study must be undertaken to clarify the conditions under which ASIT is a valuable treatment modality for dogs.     

The ACVD task force on canine atopic dermatitis (XV): fundamental concepts in clinical diagnosis.

The clinical signs of atopic dermatitis (AD) in man and in dogs are variable, and there is no single physical or historical feature that, if present, indicates the presence of AD. The initial diagnosis of AD is made clinically with the fulfillment of a combination of criteria that are strongly associated with the disease. Several schemes have been proposed in an attempt to define uniform clinical criteria for diagnosing canine AD, but no system is perfect. Once AD is considered as a possible diagnosis, other important differential diagnoses must be methodically eliminated from consideration. As a final step, once the clinician is certain that AD is probable, "allergy" tests may be conducted to provide additional evidence to "substantiate" the diagnosis. It is important to understand that allergy testing, in whatever form, is not appropriately used early in the patient evaluation as a screening test. Rather, it should be reserved, after a firm clinical diagnosis of AD has been made, to implement allergen avoidance schemes or to select allergens to be incorporated in immunotherapy formulations.     

MONITORING THE TRAUMA PATIENT

Patient monitoring devices may be considered as extensions of the veterinary clinician's senses. Many of the parameters outlined above have been used for years, without the term “monitor” being used. In this report, several patient monitoring methods have been discussed, and their advantages weighed. It is hoped that judicious use of some of these monitoring methods may aid the veterinary clinician in diagnosis and treatment of his trauma patients.     

Feline eosinophilic granuloma complex(ities): some clinical clarification

PRACTICAL RELEVANCE: The feline eosinophilic granuloma complex (EGC) comprises a group of clinically well recognised but poorly understood dermatoses that are common in cats. In many cases, lesions are severe and can be accompanied by varying degrees of (and sometimes considerable) pruritus and/or pain. In addition, lesions can be chronic and recurrent. It is, therefore, important to achieve a prompt and accurate diagnosis in order to provide optimal, often life-long, treatment for affected cats. PATIENT GROUP: There is no age predisposition or well documented breed predilection for the development of EGC lesions in cats. Some studies have reported a possible female predisposition, but this has not been consistently documented. CLINICAL CHALLENGES: The clinical diagnosis of EGC lesions is usually straightforward, but investigation of the potential underlying aetiology can pose a challenge for the clinician. Information on the indication for various diagnostic tests and their interpretation is lacking, and the tendency for these cases to be managed with chronic medical intervention prior to achieving a definitive diagnosis can further complicate the interpretation of any diagnostic investigation. In addition, successful therapeutic management of these cases can be challenging. Some cats suffer only a single episode of disease that resolves with treatment, while others have recurrent lesions and some of these can be refractory to treatment. The individual variation in both the clinical nature of the disease and the response to therapy could be related to disease severity, but could also be explained by differences in the underlying aetiopathogenesis. EVIDENCE BASE: This article reviews the published literature to discuss the complex aetiology of the EGC and present an overview of the different clinical presentations and diagnosis. A further and particular aim has been to provide some evidence-based recommendations for the management of this unusual group of dermatoses.     

II. Parameters to Monitor in the Trauma Patient – The Ideal.

Patient monitoring devices may be considered as extensions of the veterinary clinician's senses. Many of the parameters outlined above have been used for years, without the term “monitor” being used. In this report, several patient monitoring methods have been discussed, and their advantages weighed. It is hoped that judicious use of some of these monitoring methods may aid the veterinary clinician in diagnosis and treatment of his trauma patients.     

The laboratory as an aid to clinical diagnosis

The clinician may use the clinical pathology laboratory as a valuable aid to diagnosis and management, for the assessment of response to treatment, and in preventive medicine programs. Each "link in the chain," that is, sample selection, collection, handling, analysis, result reporting, and interpretation must be carefully and efficiently managed, using an informed combination of art and science, to provide a useful endpoint. This general introduction precedes more specific and detailed articles.     

Additive benefits of EFAs in dogs with atopic dermatitis after partial response to antihistamine therapy

It has been reported that 20 to 70 per cent of atopic cases in the dog can be controlled with antihistamines, though the effective antihistamine cannot be predetermined. Combination therapy with essential fatty acids (EFAS) and antihistamines has been shown to be useful in dogs. All of the work published to date has been performed in open studies, without the use of placebo, and in dogs where the aim has been to control pruritus as a symptom rather than that caused specifically by atopy. The aim of this study was to assess the combined effects of four antihistamines; hydroxyzine, chlorpheniramine, cyproheptadine and clemastine; with both an EFA supplement and a placebo of olive oil, in 25 dogs to control pruritus in clinically proven cases of atopy.     

A review of techniques for the investigation of otitis externa and otitis media

Otitis externa, inflammation of the externa ear canal, is relatively easy to diagnose based on the history and physical examination findings. The diagnosis of otitis media, inflammation of the middle ear cavity, is more challenging, with the work-up being both costly and, at times, invasive. The pathogenesis of otitis externa has been classified into predisposing, primary, and perpetuating factors. It is critical to the management of ear disease that the clinician recognize and investigate which factors are contributing to each individual patient's ear disease. Failure to identify and address the primary and/or predisposing factors is the most common cause of chronic recurrent otitis externa. Chronic inflammation of the ear canal leads to the development of the perpetuating factors, which may be the major reason for treatment failure, regardless of the primary cause of the ear disease. In this article, the predisposing, primary, and perpetuating factors involved in ear disease will be presented, along with a review of the techniques used in the diagnosis of otitis externa and otitis media.     

Pet fish formulary.

Aquarium fish are one of the most popular pets in the United States. Understanding the use of chemotherapeutics in these animals has increased markedly in recent years, and this information is now readily accessible to the private practitioner in this article. The authors introduce the veterinary clinician to the commonly used chemotherapeutics, routes of administration, species-specific precautions, and treatment tips where appropriate.