Aquagenic wrinkling in children under two years of age: Could this be a potential clinical referral tool for cystic fibrosis among non-screened populations?

BACKGROUND: Early diagnosis via newborn screening is crucial to improve clinical outcomes in patients with cystic fibrosis (CF). In resource-limited areas where newborn screening is unavailable and CF-related morbidity is high, clinical tools such as palmar aquagenic wrinkling (AW) have been considered. We report the utility of AW for possible early identification of CF in children <2 years old. METHODS: This pilot case-control study included 55 total children, 20 with confirmed CF, 10 CF carriers, and 25 healthy controls. The time to wrinkling (TTW) after hand immersion in water was recorded, and relationships between TTW, demographic and clinical variables, and validated diagnostic tests were analyzed. RESULTS: Wrinkling was observed in children <2 years of age, and median TTW was significantly lower among those with CF (3 min) compared to carriers or healthy controls (12 and 14 min, respectively). Higher immunoreactive trypsinogen and sweat chloride levels were associated with lower TTW (p < 0.001). In this predominantly Caucasian cohort, children with F508del had the lowest TTW. Six minutes of hand immersion offered a sensitivity of 85% and a specificity of 91%, suggesting a practical and effective test duration for this age. There was no evidence that nutritional status affected TTW. CONCLUSION: Our data confirm the role of AW in CF, validate test utility among young children, and analyze relationships between TTW, immunoreactive trypsinogen, sweat chloride levels, and CF-causing mutations. Despite test limitations, in children with suspected CF from non-screened populations, utility of AW in enabling early referral and diagnosis needs further exploration.