دانلود کتاب PERP 2024 – خود ارزیابی – برنامه آموزشی و بازنگری اطفال

AAP PREP 2024 – Question 1/267 – Allergy Question 1/1

An 8-year-old is being evaluated before undergoing skin-prick allergy testing. They have a history of moderate persistent asthma, mild atopic dermatitis, and severe allergic rhinitis. Two weeks ago, they were evaluated by their pediatrician for a cough and wheezing and a 5-day course of oral steroids was prescribed. Their medications include daily inhaled corticosteroids, a daily intranasal steroid, an oral antihistamine at bedtime, and a short-acting β-agonist inhaler as needed. The child uses emollients for her dry skin daily and a low-potency topical steroid cream on occasion, most recently 2 months ago. Of the following, the factor MOST likely to interfere with this child’s diagnostic testing is their B. inhaled corticosteroid use D. recent oral corticosteroid use

Correct answer is C

PREP Pearl(s)

Allergy testing should be obtained only in conjunction with a thorough history and physical examination. Skin-prick testing and serum-specific IgE tests identify immediate hypersensitivity reactions to specific allergens, which may facilitate selective avoidance and immunotherapy. Oral and topical antihistamines interfere with skin-prick testing, and their use must be discontinued before testing.

Critique

Of the response choices, oral antihistamine use is most likely to interfere with skin-prick testing (SPT). Skinprick testing is performed by trained allergists in the office setting to detect an IgE response to specific allergens. Testing involves puncturing the skin and introducing specific allergens into the epidermal layer. The resulting wheal and erythema are measured. Histamine is used as a positive control and saline as a negative control. Because histamine is an important wheal and flare response mediator, antihistamine use affects the interpretation of SPT. Short courses of oral corticosteroids and daily inhaled or intranasal steroids do not affect SPT results. Although use of potent topical steroids may affect SPT results, the child in the vignette used only low-potency topical steroids, and their last use was 2 months ago. Atopic dermatitis is a contraindication for SPT only if the location and severity of skin inflammation interfere with interpretation of the test. The childin the vignette has mild atopic dermatitis, which should not interfere with SPT. Exposure to allergens with subsequent observation of the clinical response in a controlled setting is the reference standard for diagnostic allergy testing (eg, oral food challenge, aeroallergen organ provocation). However, at times these tests may not be practical or appropriate (owing to patient safety concerns). Skinprick and serum-specific IgE testing are used to identify specific food and environmental triggers with IgEmediated immediate hypersensitivity reactions. The results guide selective avoidance and immunotherapy (for refractory cases). These tests are not useful in identifying T-cell mediated delayed reactions.