A 24-year-old woman comes to the office with a pruritic rash on her arms and legs; it has been present on and off for most of her life. Examination of the posterior left leg reveals erythematous patches and papules, as shown in the exhibit.
A similar rash is present on the right leg and bilateral antecubital fossae. Which of the following cytokines primarily initiated her current exacerbation?

Question

A 24-year-old woman comes to the office with a pruritic rash on her arms and legs; it has been present on and off for most of her life.  Examination of the posterior left leg reveals erythematous patches and papules, as shown in the exhibit. 
 A similar rash is present on the right leg and bilateral antecubital fossae.  Which of the following cytokines primarily initiated her current exacerbation?

Quizplus · Accepted Answer

This patient has atopic dermatitis, an inflammatory condition characterized by acute exacerbations of dry, pruritic, erythematous patches, papules, and/or vesicles. As in this patient, flexural regions (eg, antecubital and popliteal fossae) are commonly affected in adults. The pathogenesis of atopic dermatitis involves immune dysregulation and genetically mediated skin barrier dysfunction (eg, filaggrin mutation). The epidermal dysfunction increases cutaneous exposure to environmental allergens, which induce a Th2-predominant immune response. Key Th2 cytokines that trigger acute inflammation in atopic dermatitis are IL-4 and IL-13, and mechanisms include the following: Stimulation of plasma cell IgE production, which facilitates allergen sensitization and inflammation Suppressed expression of epidermal barrier components, which enhances Staphylococcus aureus colonization and inflammation Inhibition of Th1-type immune response and antimicrobial peptide production, which facilitate secondary microbial infections that complicate atopic dermatitis (Choice B) IL-8 and C3b are involved in neutrophil migration and activation in bacterial infections. IL-8 attracts neutrophils to infected areas, whereas C3b opsonizes pathogens for phagocytosis. This patient has no sign of infection (eg, cellulitis), such as tenderness, fever, or drainage. (Choice C) IL-12 and interferon-gamma are involved in granuloma formation and host defense against mycobacterial infections (eg, enhanced intracellular killing of tuberculosis in phagolysosomes). (Choice D) IL-17 and IL-23 are involved in the pathogenesis of psoriasis. Plaque psoriasis typically presents as pruritic, erythematous plaques with thick, silvery scales, which are not seen in this patient. In addition, its classic distribution involves the extensor, not flexor, surfaces of elbows and knees. (Choice E) TNF-alpha and IL-1 are involved in the pathogenesis of septic shock. Endotoxins in the outer membrane of gram-negative bacteria induce the release of endogenous pyrogen (eg, IL-1, prostaglandins) and inflammatory mediators (eg, TNF-alpha), leading to fever, hypotension, increased vascular permeability, and organ failure. Educational objective: Atopic dermatitis presents with dry, erythematous patches or papules that are caused in part by a Th2-skewed immune response. Th2 cytokines (eg, IL-4, IL-13) stimulate IgE production, suppress epidermal barrier component expression, and impair host immune responses against secondary microbial infections. __________ References: Skin barrier abnormalities and immune dysfunction in atopic dermatitis. (http://www.ncbi.nlm.nih.gov/pubmed/32326002)

A 24-Year-Old Woman Comes to the Office with a Pruritic