Aquagenic Wrinkling of Skin: A Screening Test for Cystic Fibrosis

Abstract

Objective

To study the utility of aquagenic wrinkling as screening test for children with cystic fibrosis.

Design

Evaluation of diagnostic test.

Setting

Pediatric Chest Clinic, and Pediatric Wards of a tertiary care hospital in New Delhi.

Participants

Three groups (children with cystic fibrosis, carriers of cystic fibrosis, and controls).

Methods

Time taken to develop aquagenic wrinkling was measured. The test was performed by asking the enrolled subject to put their one hand in water and was checked for development of wrinkling every minute, and a photograph was also taken every minute.

Results

A total of 64 children with cystic fibrosis, 64 controls and 64 carriers were enrolled in the study. Median (IQR) time to develop aquagenic wrinkling in the three groups was 2 (1.5,3) minutes, 4 (3,5) minutes and 8 (5,11) minutes, respectively. The optimal cut-off was calculated as 3 minutes by Receiver operating characteristic curve with a sensitivity and specificity for identification of children with cystic fibrosis as 81% and 57%, respectively. The area under curve was 76.5%. The 3 minute cut-off for development of aquagenic wrinkling was applied to 54 children referred for sweat test. 20 children had sweat chloride values of ≥60 mEq/l and diagnosed as cystic fibrosis. 15 of these developed aquagenic wrinkling at ≤3 minutes, giving a sensitivity of 75%.

Conclusions

In places with no facility for sweat test, children with phenotype compatible with cystic fibrosis who develop aquagenic wrinkling in 3 minutes may be diagnosed as probable cystic fibrosis and referred for confirmation by sweat test.

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