Deficient cutaneous response to PHA-P in healthy puppies from a kennel with a high prevalence of demodicosis.

Intradermal injection of phytohemagglutinin was used to evaluate the integrity of cell-mediated immunological reactions in Doberman puppies thought to be predisposed to demodicosis. Results indicate a statistically significant deficiency of cutaneous delayed response in these dogs when compared with age matched Beagles, adult Dobermans or random control dogs of various ages and breeding. The high prevalence of demodicosis in the kennel of origin may have been due to the observed deficiency of cutaneous immune function.     

Identification of allergens responsible for canine cutaneous adverse food reactions to lamb, beef and cow's milk

Lamb, beef and cow's milk are common causes of cutaneous adverse food reactions in dogs. The aim of this study was to identify the proteins responsible for cutaneous adverse reactions to these foods. Ten dogs with allergen-specific serum immunoglobulin (Ig)E to lamb, beef and cow's milk were included in the study. These dogs had been diagnosed with cutaneous adverse food reactions by convincing clinical history and food-elimination diet trials followed by challenge exposure. Sera were analysed by enzyme-linked immunosorbent assay with bovine proteins and SDS-PAGE immunoblots with lamb, beef and cow's milk extracts. All the dogs had specific IgE against bovine IgG, and it was the only protein in the cow's milk extract that bound IgE from the sera studied. In the lamb and beef extracts, the major allergens recognized by the specific IgE of most sera had molecular masses between 51 and 58 kDa, which were identified as phosphoglucomutase and the IgG heavy chain. Other IgE-binding proteins with molecular masses of 27, 31, 33, 37 and 42 kDa were also detected with some sera. Our results indicate that bovine IgG is a major allergen in cow's milk and hence it appears to be a source of cross-reactivity with beef and probably with lamb because of the high homology with ovine immunoglobulins. These results are similar to those found for meat allergy in humans. However, this is the first time that phosphoglucomutase has been identified as an important allergen involved in allergic reactions to lamb and beef.     

Treatment of severe adverse cutaneous drug reactions with human intravenous immunoglobulin in two dogs

Severe adverse cutaneous reactions were documented in two dogs with acute skin lesions and systemic signs after exposure to several oral and injectable drugs. Because of the high morbidity and mortality rates of many severe cutaneous drug reactions and a poor response to supportive care, wound management, and conventional immunosuppressive therapy, human intravenous immunoglobulin (IVIG) was infused on 2 consecutive days (1 g/kg per day) after informed consent was received. Human IVIG, with supportive care, resulted in rapid resolution of dermatological and systemic signs in both dogs; this treatment may be considered in other cases of severe cutaneous drug reactions.     

A Prospective Study of Radiation Therapy for the Treatment of Grade 2 Mast Cell Tumors in 32 Dogs

Surgery, chemotherapy, and irradiation have been used singly or in combination to treat dogs with cutaneous grade-2 mast cell tumors (MCT). However, optimal treatment has not been established. At The Animal Medical Center, 32 dogs with grade 2, stage 0 MCT received cobalt radiation treatment to a dose of 54 Gy; 94% had a disease-free interval of 1 year. The 2–,3–,4–, and 5–year disease-free intervals were 86%. Survival rates were 100% for 1 year and 96% for 2 to 5 years, with only 1 death caused by MCT. Primary site was not a prognostic factor for survival in this study. Minimal toxicity was observed and was limited to acute cutaneous reactions. Late-term reactions to radiation therapy were mild and considered acceptable in all cases. No deaths occurred due to treatment, and no dog was eliminated from the study because of radiation therapy toxicity. Radiation therapy appears to be an effective treatment for dogs with grade 2, stage 0 MCT.     

The ACVD task force on canine atopic dermatitis (X): is there a relationship between canine atopic dermatitis and cutaneous adverse food reactions?

In humans, allergies to foods are known to induce skin lesions in some patients with atopic dermatitis. This is particularly evident in infants with severe atopic dermatitis. Food allergy in humans is an IgE-mediated hypersensitivity in most cases, and thus has the same (or very similar) pathogenic mechanism of disease induction as environmental allergen-induced atopic dermatitis. Cutaneous adverse food reactions and atopic dermatitis in dogs are often indistinguishable from each other on historical and clinical grounds alone. Limited current evidence suggests that dogs with cutaneous adverse food reactions may be predisposed to developing atopic dermatitis. However, confirmation of any association between these two diseases in dogs awaits further elucidation of the pathogenic mechanism of cutaneous adverse food reactions, and epidemiological studies of the relative prevalence of these diseases in relation to each other and the general population.     

Immediate type hypersensitivity in dogs induced by storage mites

Results of intradermal skin tests on 53 dogs, employing storage mite extracts as antigen, indicated that storage mite allergy is fairly common. Only four of 29 dogs exhibiting no allergic symptoms showed skin reactions to the most common storage mite, Acarus siro, whereas 18 out of 24 dogs with symptoms assumed to be associated with allergy showed such reactions. The passive cutaneous transfer test revealed that an immediate type hypersensitivity reaction was involved.     

Cell-mediated immunity in the prepatent primary infection of dogs with Echinococcus granulosus

Cell-mediated immunity was studied in 21 parasite-naive dogs by transformation of peripheral lymphocytes with phytohemagglutinin (PHA), concanavalin A (Con A), or hydatid fluid protein (HFP) at 29 days of a primary infection with Echinococcus granulosus, and by delayed cutaneous hypersensitivity to HFP at 36 days of the infection. Infection depressed significantly the ability of unstimulated cells to proliferate but enhanced the response to Con A. The lymphocytes of four dogs reacted to HFP significantly above the average, and one dog exhibited cutaneous reactivity to 0.2 micrograms of HFP. Five or 1 but not 0.2 micrograms of HFP produced non-specific skin reactions in parasite-naive dogs. The 7 dogs with the highest reactivity to PHA or Con A had significantly fewer parasites than the 7 less reactive dogs. The differences in other parasite characteristics were not significant in the 7 dogs with the greatest or smallest reactivities. Correlation tests showed an inverse correlation of PHA reactivity with establishment and maturation of parasites, of Con A reactivity with growth and maturation, and of HFP with maturation.     

Evaluation of serum obtained from atopic dogs with dermatitis attributable to Malassezia pachydermatis for passive transfer of immediate hypersensitivity to that organism

OBJECTIVE: To determine the functionality of canine anti-Malassezia IgE via the passive transfer of immediate hypersensitivity localized to the skin (ie, cutaneous anaphylaxis) from atopic dogs with dermatitis attributable to overgrowth of Malassezia pachydermatis (Malassezia dermatitis [MD]) to healthy recipient dogs by use of the Prausnitz-Küstner (P-K) technique. ANIMALS: 7 clinically normal dogs, 32 atopic dogs with MD, serum from 11 atopic dogs with MD, and 3 healthy dogs without prior sensitization to M pachydermatis. PROCEDURE: Serum from atopic dogs with MD was used for P-K tests in 3 clinically normal recipient dogs. Serial dilutions of untreated, heat-inactivated, IgE-absorbed, and bovine serum albumin (BSA)-absorbed (control) aliquots of serum were injected ID in triplicate for dermal sensitization. Twenty-four, 48, and 72 hours later, a crude extract of M pachydermatis was injected ID into the sites used for sensitization injections, and immediate hypersensitivity reactions were graded on a 4-point scale. RESULTS: Untreated serum caused P-K reactivity beginning 24 hours after passive sensitization and persisting through 72 hours (titers, 1:32 to 1:64). Heat inactivation and IgE-absorption of serum eliminated P-K reactivity, whereas treatment of serum with BSA did not. CONCLUSIONS AND CLINICAL RELEVANCE: Analysis of P-K test results supports the passive transfer of cutaneous anaphylaxis by anti-Malassezia IgE and indicates it is functional in type-1 hypersensitivity reactions of atopic dogs with MD. Reduction or blockade of anti-Malassezia IgE in atopic dogs with MD may provide better clinical control of the disease.     

IgE reactivity to milk components in dogs with cutaneous adverse food reactions

We investigated the IgE reactivity to crude and purified milk antigens in the sera of 112 dogs with cutaneous adverse food reactions (CAFRs). Of the 112 dogs, 33 (29%) had specific IgE for crude milk antigens. In the dogs with milk-specific IgE, IgE reactivity to casein, bovine serum albumin (BSA), α-lactalbumin, β-lactoglobulin, and bovine IgG were 81%, 85%, 39%, 27%, and 35%, respectively. Casein and BSA may be important allergens in dogs with CAFRs. Some canine vaccines contain casein hydrolysate as a stabilizer and the pooled serum with anti-casein IgE showed IgE reactivity to the vaccines containing it. Information about IgE reactivity to casein in dogs with CAFRs could be useful for predicting adverse reactions to the vaccines including casein hydrolysate.     

Identification of the most common cutaneous neoplasms in dogs and evaluation of breed and age distributions for selected neoplasms

OBJECTIVE-To identify the most common cutaneous neoplasms in dogs and evaluate breed and age distributions for selected neoplasms. DESIGN-Retrospective epidemiological study. SAMPLE-Records available through the Veterinary Medical Database of dogs examined at veterinary teaching hospitals in North America between 1964 and 2002. PROCEDURES-Information on tumor type and patient breed and age was collected. Incidence and odds ratios with 95% confidence intervals were calculated. RESULTS-Records of 1,139,616 dogs were reviewed. Cutaneous neoplasms were diagnosed in 25,996 of these dogs; records for the remaining 1,113,620 dogs did not indicate that cutaneous neoplasms had been diagnosed, and these dogs were considered controls. The most frequent age range for dogs with cutaneous neoplasms was 10 to 15 years. Lipoma, adenoma, and mast cell tumor were the most common skin tumor types. CONCLUSIONS AND CLINICAL RELEVANCE-Results supported previously reported data regarding cutaneous neoplasia in dogs but provided updated information on the most common skin tumors and on age and breed distributions.     

Use of hyaluronidase for the treatment of extravasation of chemotherapeutic agents in six dogs

Six dogs had perivascular extravasation of antineoplastic agents during IV administration. Treatment with 300 units of hyaluronidase injected locally in the affected site was initiated following the extravasation event. Injections were repeated weekly until signs of toxic effects within the tissues resolved satisfactorily. All dogs recovered within 6 weeks, and residual fibrosis at the extravasation sites most was considered minimal. Many chemotherapeutic agents cause severe cytotoxic reactions when extravasated during cycles of chemotherapy, resulting in tissue necrosis with ulceration and sloughing of skin during the following weeks. Surgical treatments and skin grafting are often necessary to achieve healing. The sequelae of extravasation may result in discontinuation of chemotherapy or euthanasia of the animal. Hyaluronidase appears to be a safe treatment for the adverse effects of extravasation of various chemotherapeutic agents and may be used effectively to reduce the severity of cutaneous toxicosis.     

Use of high-frequency ultrasonography for evaluation of skin thickness in relation to hydration status and fluid distribution at various cutaneous sites in dogs

OBJECTIVE: To assess the usefulness of high-frequency diagnostic ultrasonography for evaluation of changes of skin thickness in relation to hydration status and fluid distribution at various cutaneous sites in dogs. ANIMALS: 10 clinically normal adult dogs (6 males and 4 females) of various breeds. PROCEDURES: Ultrasonographic examination of the skin was performed before and after hydration via IV administration of an isotonic crystalloid solution (30 mL/kg/h for 30 minutes). A 13-MHz linear-array transducer was used to obtain series of ultrasonographic images at 4 different cutaneous sites (the frontal, sacral, flank, and metatarsal regions). Weight and various clinicopathologic variables (PCV; serum osmolality; and serum total protein, albumin, and sodium concentrations) were determined before and after the infusion. These variables and ultrasonographic measurements of skin thickness before and after hydration were compared. RESULTS: Among the 10 dogs, mean preinfusion skin thickness ranged from 2,211 microm (metatarsal region) to 3,249 microm (sacral region). Compared with preinfusion values, weight was significantly increased, whereas PCV; serum osmolality; and serum total protein, albumin, and sodium concentrations were significantly decreased after infusion. After infusion, dermal echogenicity decreased and skin thickness increased significantly by 21%, 14%, 15%, and 13% in the frontal, sacral, flank, and metatarsal regions, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Cutaneous site and hydration were correlated with cutaneous characteristics and skin thickness determined by use of high-frequency ultrasonography in dogs. Thus, diagnostic ultrasonography may be a useful tool for the noninvasive evaluation of skin hydration in healthy dogs and in dogs with skin edema.     

Cutaneous histiocytosis in dogs

Multifocal cutaneous histiocytic lesions were recognized in 9 dogs. Clinically, the dogs had multiple erythematous plaques or nodules in the skin (1 to 5 cm diameter). Histologically, the lesions were comprised of dermal or pannicular infiltrates of large histiocytic cells, with varying numbers of other inflammatory cells intermixed. By electron microscopy, the cells resembled those of canine cutaneous histiocytoma. The lesions seemed to wax and wane and appeared in new sites, regardless of treatment. The dogs ranged in age from 2 to 13 years; 7 dogs were under 6 years of age. Both sexes and various breeds were represented. An infectious agent could not be identified.     

Hypotension and cutaneous reactions associated with intravenous administration of etoposide in the dog

A study was undertaken to determine the pressor and toxic effects of etoposide, an antineoplastic agent, when administered IV in 0.9% sodium chloride solution (0.4 mg of etoposide/ml) over a 30-minute period to dogs at a dosage of 40 mg/m2 of body surface. On day 1, 6 adult German Shorthaired Pointers were anesthetized with halothane, and blood pressures were measured via a femoral artery catheter before, during, and after the etoposide was administered. Systolic, diastolic, and mean blood pressures of each dog decreased [corrected] significantly (P less than 0.01) within 30 minutes after initiation of etoposide infusion. On day 3, when the dogs were not anesthetized, etoposide was again administered to each dog, using the same dosage. Each dog developed a moderate to severe cutaneous reaction characterized by moderate to severe pruritus, urticaria, and swelling of the head and extremities that began during the second infusion of etoposide. These same cutaneous reactions were seen on day 30, when etoposide was administered to 3 of the previously treated dogs and 2 previously untreated Beagles. We concluded that the administration of the commercial preparation of etoposide is likely to cause a significant reduction in blood pressure of anesthetized dogs, and that the drug is likely to induce a moderate to severe cutaneous reaction when administered to unanesthetized dogs.     

Impact of tumour depth, tumour location and multiple synchronous masses on the prognosis of canine cutaneous mast cell tumours

The goal of this study was to determine the significance of tumour depth, tumour location and multiple synchronous tumour masses for the prognostic evaluation of canine cutaneous mast cell tumours (MCTs). The study population consisted of 100 formalin-fixed, paraffin-embedded cutaneous MCTs that had been surgically removed from 100 dogs and submitted to the Diagnostic Center of Population and Animal Health at Michigan State University between 1998 and 2001. None of the dogs had received chemotherapy or radiation therapy. For each case the following data were obtained from the referring veterinarians: sex, breed, weight, age at diagnosis, diagnostics performed, adjunct medications given at the time of surgery, tumour location, number of tumour masses, tumour recurrence (development of MCTs at the surgical site), development of additional MCTs at distant sites (outside the surgical margins), tumour duration before removal, survival time and cause of death, if applicable. Tumour depth was determined through microscopic evaluation of 5 microm sections stained with haematoxylin and eosin. Based on univariable and multivariable survival analysis, dogs with multiple synchronous cutaneous MCTs at the time of diagnosis have a worse prognosis compared with dogs with single tumours. Additional treatment beyond surgical excision alone should be considered for these animals. Older dogs and Boxers with cutaneous MCTs were at higher risk to develop additional MCTs at distant sites (outside the surgical margins), and older and male dogs with cutaneous MCTs had significantly shorter survival times. Univariable analysis also determined that dogs with cutaneous MCTs located on the head and neck had an increased risk of additional MCT development at distant sites and that sterilized dogs with cutaneous MCTs had shorter survival times. However, these findings were not confirmed by multivariable analysis. Tumour depth was of no prognostic significance for dogs with cutaneous MCTs.     

Immunologic responses against hydrolyzed soy protein in dogs with experimentally induced soy hypersensitivity

OBJECTIVE: To assess whether dogs with experimentally induced type I hypersensitivity against soy protein would respond to soy hydrolysate and develop cutaneous or gastrointestinal tract reactions after intradermal and oral challenge exposure. ANIMALS: 12 na?ve Beagle pups (9 sensitized and 3 control dogs). PROCEDURE: 9 dogs were sensitized against soy protein by administration of allergens during a 90-day period. After the sensitization period, serum concentrations of soy-specific IgE were determined and an intradermal test was performed to confirm the dogs were sensitized against soy protein. An intradermal challenge test and an oral challenge test with native and hydrolyzed soy protein were conducted on 6 sensitized and 2 control dogs. RESULTS: High serum concentrations of soy-specific IgE and positive results for the intradermal test were observed for the 9 sensitized dogs after completion of the sesitization process. Sensitized dogs challenge exposed with hydrolyzed soy protein had a reduced inflammatory response after intradermal injection and no clinical response after an oral challenge exposure, compared with responses after intradermal and oral challenge exposure with native soy protein. CONCLUSIONS AND CLINICAL RELEVANCE: Soy-sensitized dogs did not respond to oral administration of hydrolyzed soy protein. Thus, hydrolyzed soy protein may be useful in diets formulated for the management of dogs with adverse reactions to food.     

Immune responses in dogs with cutaneous adverse food reactions

Adverse food reactions (AFR) in dogs are reactions due to apparently harmless food antigens, with an unknown aetiology, i.e. immunopathogenesis. Despite the entry of food allergens via the intestinal tract, in the majority of dogs with AFR, clinical symptoms are only associated with the skin (CAFR). In the present review, factors are presented of relevance in triggering the differentiation of naive T cells into effector T cell types and the role of these T cell types in allergy. More specifically, the allergic immune responses in intestine and skin are discussed in this article as well as the potential pathways, e.g. homing of antigen presenting cells or allergen-induced T cells to the skin, of induction of cutaneous symptoms.     

A prospective comparison between stabilized glutaraldehyde and chlorhexidine gluconate for preoperative skin antisepsis in dogs

OBJECTIVE: To compare the efficacy of 0.3% stabilized glutaraldehyde and alcohol (SG+A), 0.3% SG and water (SG+W), and 4% chlorhexidine gluconate tincture (CG+A), as skin disinfectants in dogs undergoing ovariohysterectomy. STUDY DESIGN: Prospective, blinded clinical study. ANIMALS: One hundred and twenty-one dogs. METHODS: Cutaneous bacterial colony forming units (CFU) from the perioperative site after skin preparation, after antisepsis, and after surgery (incisional and paramedian), were quantified. The influence of high initial bacterial counts (> or =150 CFU) and surgical time on antibacterial efficacy was examined and the proportion of dogs from which Staphylococcus intermedius was cultured, determined. Perioperative skin reactions and wound infections were documented. RESULTS: All 3 antiseptic solutions significantly and equally reduced CFU to all post-antisepsis sampling levels irrespective of surgical duration (mean surgical times 151.6, 136.2, and 149.6 minutes for CG+A, SG+A and SG+W, respectively). Median percentage reductions in CFU ranged between 99.3% and 100%. In dogs with initial high counts and disinfected with CG+A and SG+W, the incisional samples had significantly higher counts than the post-antisepsis samples. In the CG+A and SG+W groups, the proportion of post-surgery samples yielding S. intermedius was significantly higher at the incisional than the paramedian sites. Eight mild cutaneous reactions were recorded in equal proportions for the 3 solutions. There were no recorded infections. CONCLUSIONS: All 3 preparations had an equal ability to reduce and maintain low CFU counts, with minimal cutaneous reactions. CLINICAL RELEVANCE: SG solutions are safe and effective preoperative skin antiseptics for elective clean-contaminated surgical procedures.     

Primary localized nodular cutaneous amyloidosis in a male neutered Golden Retriever

Cutaneous amyloidosis occurs as primary localized form or secondary to systemic amyloidosis. In dogs, cutaneous amyloidosis is reported in association with localized plasma cell proliferation or cutaneous extramedullary plasmacytoma. Primary cutaneous amyloidosis is a very rare condition in dogs. There is paucity of information and published report on primary nodular cutaneous amyloidosis in dogs. This report describes a case of primary nodular cutaneous amyloidosis for the first time in a male Golden Retriever.     

Use of kit internal tandem duplications to establish mast cell tumor clonality in 2 dogs

Mast cell tumor (MCT) is one of the most common tumors of dogs. Some affected dogs develop multiple cutaneous tumors in various locations over months to years. In these cases, it is not clear whether the tumors have arisen de novo, or if each tumor represents a recurrence of the previously excised original tumor (ie, distant metastasis). We used the presence of an internal tandem duplication (ITD) in c-kit to demonstrate that in 2 dogs with recurrent cutaneous MCT that had developed over 1-2 years, each recurrent MCT tumor possessed an identical ITD when compared to the original MCT, indicating that the multiple tumors were clonal in origin. This study demonstrates that similar to the situation in humans, specific somatic mutations identified in oncogenes found in canine neoplasms can be used to provide evidence of tumor clonality.