Case: A 9-month-old boy has had a pruritic facial rash (A and B) that has resisted topical therapy. A topical antifungal, topical antibiotics, and 1% hydrocortisone cream have all failed to clear the eruption. Another 9-month-old boy has had a similar rash (C), with no response to topical therapy. Both infants have the same condition and a family history of atopy.
What is this condition—and can you identify the cause?