A 6-month-old infant presents with intensely pruritic erythematous eczematous patches on the cheeks, scalp and extensor surfaces of the limbs. The mother has seasonal allergic rhinitis. Total IgE is elevated. The diagnostic criterion that BEST defines this condition is:

• A Positive patch test to nickel
• B Positive Wood's lamp fluorescence of skin lesions
• C Tzanck smear showing acantholytic cells
• D Hanifin-Rajka criteria (pruritus + chronic relapsing course + typical distribution + personal/family atopy) ✓

Explanation

Atopic dermatitis is diagnosed clinically using Hanifin-Rajka criteria (or the simplified UK Working Party criteria). Major criteria include pruritus, typical morphology and distribution (flexural in older children; face/extensor in infants), chronic or chronically relapsing course, and personal or family history of atopy. Positive patch test diagnoses contact dermatitis. Wood's lamp is for tinea versicolor, erythrasma or Microsporum tinea capitis. Tzanck smear detects acantholytic cells in pemphigus/HSV.

Reference: Ghai Essential Pediatrics, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.