Retrospective evaluation of hypersensitivity reactions and anaphylaxis in dogs (2003-2014): 86 cases.

OBJECTIVE: To characterize anaphylactic reactions in dogs, including clinical signs, severity, treatments, prognosis, and estimated incidence. To determine whether glucocorticoids influence clinical recovery and survival. DESIGN: Retrospective study between January 1, 2003 and April 28, 2014. SETTING: University teaching hospital. ANIMALS: Eighty-six dogs treated for a type I hypersensitivity reaction. Nineteen dogs fulfilled the criteria for anaphylaxis, and 67 dogs had mild cutaneous reactions. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The estimated incidence was 0.04% for anaphylaxis and 0.15% for mild hypersensitivity reactions. The female:male ratio (2.3:1) was significantly higher (P = 0.032) compared to our source population (ratio of 1:1.158). Vaccines were the most frequent trigger for anaphylaxis (57.9%) and mild hypersensitivity reactions (28.4%). Seventy-four (86%) dogs had cutaneous signs, and 11 (57.9%) dogs with anaphylaxis had no cutaneous signs reported. Forty-two (48.8%) dogs received both an H1 antagonist and a glucocorticoid, 34 (39.5%) dogs received an H1 antagonist only, and 6 (6.9%) dogs received a glucocorticoid only. The majority of the dogs survived, and 1 was euthanized due to complications. Clinical signs associated with nonsurvival included respiratory signs (P = 0.006), particularly respiratory distress (P < 0.00001) and cyanosis (P < 0.00001), and circulatory shock (P = 0.005). The analysis of the interaction between etiology, clinical signs, treatment, and outcome did not show any association between pairs of variables. CONCLUSIONS: In the current study, anaphylaxis had a relatively good prognosis, and cutaneous signs were not always present. Based on the present data, the use of glucocorticoids to treat mild type I hypersensitivity reactions and anaphylaxis in dogs was not associated with clinical improvement or survival.

Potential cutaneous hypersensitivity reaction to an inactive ingredient of thyroid hormone supplements in a dog.

BACKGROUND: Although discussions about allergic reactions to thyroid supplements abound on professional forums, there is almost no information in the literature on these specific idiosyncratic drug reactions. ANIMAL: A dog with a history of hypothyroidism-associated weight gain and mild lethargy was prescribed levothyroxine tablets (0.018 mg/kg twice daily). After 19 days the dog developed a severe skin condition that was responsive to levothyroxine withdrawal, and antibiotic and glucocorticoid therapy. Three weeks later a different levothyroxine tablet was prescribed. Within 48 h the dog developed a more severe cutaneous reaction that resolved with drug discontinuation and appropriate topical care. OBJECTIVES: To confirm a possible hypersensitivity reaction and identify its chemical target. METHODS AND RESULTS: The two prescribed levothyroxine formulations shared two inactive ingredients: magnesium stearate and polyvinylpyrrolidone. Nine months after discontinuation of thyroid supplement, a formulation without either of these two compounds was used for a second re-challenge. There was no recurrence of the drug reaction and after 1.5 years of treatment the dog remains normal. CONCLUSIONS AND CLINICAL IMPORTANCE: These elements strongly suggest that this dog had an idiosyncratic reaction (likely immune-mediated) against one or both inactive ingredients in the first two formulations of levothyroxine. We are not aware of any previous confirmed delayed hypersensitivity to a thyroid supplement in a dog with the likely chemical trigger being an inactive ingredient rather than the therapeutic agent itself. We hope that this case will raise awareness about allergic reactions to thyroid supplements and allergic reactions to inactive formulation components.

Prevalence of feline blood groups in the Montreal area of Quebec, Canada.

The feline AB blood group system has clinical significance because type B cats have natural alloimmune anti-A antibodies which can cause isoerythrolysis of the newborn and life-threatening transfusion reactions. In the United States, the prevalence of type B blood is estimated to be 1% to 2%. This study determined the prevalence of feline AB blood groups among 207 potential blood donor cats that included 178 domestic cats, in the Montreal area of Quebec, Canada. Blood typing was performed using a standardized tube technique. Blood types AB and B were confirmed using a backtyping technique. The frequency of blood types among the studied population was as follows: 95.2% type A, 4.4% type B, and 0.48% type AB. Among domestic cats, the frequency was 94.4% for type A, 5% for type B, and 0.6% for type AB. The frequency of type B was higher than expected, which reinforces the recommendation to ensure blood compatibility of the recipient and donor before transfusion through typing and possibly cross-matching as well.

Prévalence des groupes sanguins félins dans la région de Montréal au Québec, Canada. Le système de groupe sanguin félin AB possède une signification clinique parce que les chats de type B ont des anticorps anti-A allo-immuns qui peuvent causer l'isoérythrolyse du nouveau-né et des réactions potentiellement mortelles lors de transfusions. Aux États-Unis, la prévalence de sang de type B est estimée à 1 % ou 2 %. Cette étude a déterminé la prévalence des groupes sanguins AB félins parmi 207 chats donneurs de sang qui comprenaient 178 chats domestiques, dans la région de Montréal au Québec, Canada. La détermination des groupes sanguins a été réalisée à l'aide d'une technique en tube normalisée. Les types sanguins AB et B ont été confirmés en utilisant une technique de détermination croisée. La fréquence des types sanguins parmi la population étudiée était la suivante : 95,2 % type A, 4,4 % type B et 0,48 % type AB. Parmi les chats domestiques, la fréquence était de 94,4 % pour le type A, de 5 % pour le type B et de 0,6 % pour le type AB. La fréquence du type B était supérieure aux prévisions, ce qui renforce la recommandation afin d'assurer la compatibilité du sang du récipiendaire et du donneur avant la transfusion par la détermination du groupe sanguin et aussi la possibilité d'une épreuve de compatibilité croisée.(Traduit par Isabelle Vallières).