27 Questions
What is the characteristic feature of atopic individuals in terms of eosinophils and IgE levels?
Higher numbers of eosinophils and total levels of IgE
What are the conditions that favor the production of IgE antibodies according to the text?
Immune system challenged by small quantities of antigen and basophils producing IL-4
What triggers class switching to IgE in activated, antigen-specific B cells?
TH2 T cells secreting IL-4 and other cytokines
What type of substances drive type I hypersensitivity responses according to the text?
Proteins or chemicals that chemically modify human proteins
What is the characteristic feature of a late-phase reaction following mast cell activation by an allergen?
Widespread swelling at the injection site
Which type of hypersensitivity reaction is triggered by chemokines, cytokines, and leukotrienes synthesized by mast cells?
Type III
What is the primary role of regulatory T cells (Tregs) in non-allergic individuals exposed to environmental antigens that drive type I responses?
Inhibiting Th2 cell responses against allergens
In individuals with a predisposition towards allergies, what immune responses are driven by environmental antigens?
Th2 responses
What is the primary trigger for allergic asthma?
Inhaled allergens activating mast cells in the lower airways
Which type of hypersensitivity response is characterized by raised, itchy swellings on the skin?
Type I (Immediate)
What is the hallmark feature of chronic asthma?
Total occlusion of airways by mucus plugs
Which condition results from prolonged allergic responses in the skin characterized by chronic inflammation and itching skin rash?
Eczema (atopic dermatitis)
Which receptor antagonism is responsible for the sedation caused by antihistamines?
Muscarinic receptors
What is a potential adverse effect of antihistamines in children, as mentioned in the text?
Hallucinations
Which generation of antihistamines is more likely to cause CNS penetration due to their ability to cross the blood-brain barrier?
1st generation
What symptom relief is specifically mentioned as an additional use of diphenhydramine?
Motion sickness
Compared to 1st generation antihistamines, what is a distinguishing feature of 2nd generation antihistamines?
Less likely to cross the blood brain barrier
What is the primary reason for loratadine and cetirizine to have less sedation and adverse effects compared to diphenhydramine?
They exhibit minimal metabolism by the liver
Which antihistamine is excreted primarily in the feces, inhibits absorption with fruit juices, and has minimal hepatic metabolism?
Fexofenadine
Why does levocetirizine have a high bioavailability compared to fexofenadine?
It does not undergo significant hepatic metabolism
Which antihistamine has the highest bioavailability and is distributed in all tissues including the CNS?
Cetirizine
What is the primary difference in the metabolism of loratadine compared to cetirizine and fexofenadine?
Metabolized via CYP2D6 and 3A4 to active metabolite
Which receptor is blocked by some antihistamine drugs causing dry mouth and constipation?
Muscarinic
Which of the following antihistamines is most likely to cross the blood-brain barrier?
Diphenhydramine
What is a significant difference in mechanism of action between fexofenadine and diphenhydramine?
Fexofenadine is a selective H1 receptor antagonist, while diphenhydramine is non-selective.
Which antihistamine is least likely to interact adversely with fruit juices?
Fexofenadine
In anaphylaxis treatment with epinephrine, which antihistamine may be used as an adjunctive therapy?
Fexofenadine
Test your knowledge on atopy and allergens, including how improved heating and cooling systems can contribute to the spread of allergens. Learn about the predisposition towards hypersensitivity reactions and IgE responses in individuals.
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