A 4-month-old infant has pruritic, erythematous, weeping vesiculopapular lesions on the cheeks, forehead, and scalp, sparing the diaper area. Family history is positive for allergic rhinitis in the father. Total IgE is elevated. Which mediator is most central to the pathophysiology of this condition?
- A IL-4 and IL-13 promoting Th2 polarization and IgE isotype switching ✓
- B IL-17 and IL-22 promoting neutrophilic inflammation
- C IFN-gamma and IL-12 promoting Th1 response
- D TNF-alpha and IL-1 from macrophage activation
Explanation
Infantile atopic dermatitis (eczema) is a Th2-mediated inflammatory condition. IL-4 and IL-13 are the pivotal cytokines driving Th2 polarization, promoting IgE class switching (elevated total IgE), mast cell activation, and eosinophilia. IL-4 also upregulates IL-4Rα expression, amplifying Th2 signaling. Dupilumab (anti-IL-4Rα monoclonal antibody) blocking both IL-4 and IL-13 signaling is approved for atopic dermatitis, validating this pathway as central. IL-17/IL-22 are central in psoriasis (Th17). Sparing of the diaper area (high humidity protects) and face predilection with family atopy history are classic for infantile atopic eczema.
Reference: Ghai Essential Pediatrics, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.