Chapter 5 Allergy Flashcards
What is an allergic reaction?
“An overreaction of the immune system to a normally harmless substance”
What are IgE-mediated allergies also known as?
“Type I hypersensitivities”
What characterizes IgE-mediated allergies?
“Immediate onset after exposure to allergen”
What are common IgE-mediated allergies in horses?
“Culicoides hypersensitivity and urticaria”
What is Culicoides hypersensitivity?
“A seasonal
What are the clinical signs of Culicoides hypersensitivity?
“Pruritus
What factors influence the prevalence of Culicoides hypersensitivity?
“Environmental exposure
What are the immunologic mechanisms involved in Culicoides hypersensitivity?
“Production of allergen-specific IgE
What is mast cell sensitization?
“Binding of IgE to tissue mast cells”
What is the Prausnitz-Küstner reaction?
“A method to transfer allergic reactions via IgE”
What role do Th2 cells and regulatory T cells play in Culicoides hypersensitivity?
“Increased Th2 cell responses and reduced regulatory T cell functions”
What diagnostic techniques are used for detecting allergen-specific IgE in horses?
“Intradermal allergy testing and serological assays”
What is intradermal allergy testing?
“A method where allergens are injected into the skin”
What is the main goal of allergy testing?
“To identify the causing allergen(s)”
What are the limitations of serological allergy testing in horses?
“Poor performance due to numerous false positives”
What treatments are available for IgE-mediated allergies in horses?
“Symptomatic treatments like steroids
What preventive measures can be taken for horses with Culicoides hypersensitivity?
“Managing turn-out times
What is urticaria in horses?
“A condition characterized by skin lesions”
What are common causes of urticaria in horses?
“Food allergens
What histopathological findings are associated with urticaria?
“Dermal edema with eosinophilic and/or lymphocytic infiltrates”
What is recurrent airway obstruction (RAO) in horses?
“A respiratory condition suspected to be mediated by hypersensitivity type I”
What triggers RAO in susceptible horses?
“Inhaled molds and organic dusts”
What is the controversy regarding IgE’s role in RAO?
“Studies show conflicting results”
What is the prognosis for horses with IgE-mediated allergies?
“Allergies typically recur with allergen exposure”
What is the difference between an allergic reaction and an anaphylactic reaction?
“Anaphylactic reactions are severe and life-threatening”
What does the term ‘sensitization’ refer to in the context of allergies?
“The process where IgE binds to high-affinity receptors on mast cells”
What is the main allergen responsible for Culicoides hypersensitivity?
“Salivary allergens from Culicoides midges”
What percentage of Icelandic horses exported to Europe develop Culicoides hypersensitivity?
“26-72%”
What are common clinical signs of Culicoides hypersensitivity in horses?
“Pruritus and alopecia”
What is the role of regulatory T cells in allergies?
“They reduce the allergic response”
What is the function of histamine in allergic reactions?
“Causes vasodilation and increased vascular permeability”
What is the primary method for diagnosing urticaria in horses?
“Intradermal allergy testing”
What type of hypersensitivity is urticaria in horses believed to be?
“Type I hypersensitivity”
What is a common treatment for severe clinical signs of allergies in horses?
“Steroids and anti-histamines”
What are the main goals of allergy testing in horses?
“Identify the causing allergen(s)”
What environmental conditions can influence the prevalence of Culicoides hypersensitivity?
“Temperature and humidity”
What is a major complication associated with Culicoides hypersensitivity if not treated?
“Secondary bacterial infections”
How do Th2 cells contribute to allergies?
“They produce pro-inflammatory cytokines”
What is the role of IgE in allergic reactions?
“Binds to mast cells and basophils”
What is the effect of repeated allergen exposure in allergic horses?
“Increased allergen-specific IgE production”
What is the importance of mast cell degranulation in allergies?
“Triggers the release of inflammatory mediators”
What is a key diagnostic feature of intradermal allergy testing?
“Formation of a wheal”
What is the first step in managing an allergic horse?
“Identifying and avoiding the allergen”
What is a potential side effect of steroid treatment in horses?
“Decreased immune response”
What does the term ‘inflamm-aging’ refer to?
“Chronic low-grade inflammation associated with aging”
What is the role of cytokines in allergies?
“They increase vascular permeability and inflammation”
What are the clinical signs of recurrent airway obstruction (RAO) in horses?
“Mucus production
