Aquagenic Wrinkling of Skin: A Screening Test for Cystic Fibrosis

ABSTRACT

Objectives: To study the utility of aquagenic wrinkling asscreening test for children with cystic fibrosis.Design: Evaluation of diagnostic test.Setting: Pediatric Chest Clinic, and Pediatric Wards of a tertiarycare hospital in New Delhi.Participants: Three groups (children with cystic fibrosis,carriers of cystic fibrosis, and controls).Method: Time taken to develop aquagenic wrinkling wasmeasured. The test was performed by asking the enrolled subjectto put their one hand in water and was checked for development ofwrinkling every minute, and a photograph was also taken everyminute.Results: A total of 64 children with cystic fibrosis, 64 controls and64 carriers were enrolled in the study. Median (IQR) time todevelop aquagenic wrinkling in the three groups was 2 (1.5,3)minutes, 4 (3,5) minutes and 8 (5,11) minutes, respectively. Theoptimal cut-off was calculated as 3 minutes by Receiveroperating characteristic curve with a sensitivity and specificityfor identification of children with cystic fibrosis as 81% and 57%,respectively. The area under curve was 76.5%. The 3 minutecut-off for development of aquagenic wrinkling was applied to 54children referred for sweat test. 20 children had sweat chloridevalues of ≥60 mEq/l and diagnosed as cystic fibrosis. 15 of thesedeveloped aquagenic wrinkling at ≤3 minutes, giving a sensitivityof 75%.Conclusion: In places with no facility for sweat test, childrenwith phenotype compatible with cystic fibrosis who developaquagenic wrinkling in 3 minutes may be diagnosed as probablecystic fibrosis and referred for confirmation by sweat tes