Frequency of aquagenic palmoplantar keratoderma in cystic fibrosis: a new sign of cystic fibrosis?

BACKGROUND: Aquagenic palmoplantar keratoderma (APPK), also known as aquagenic wrinkling of the palms, is characterized by oedema of palms and/or soles, whitish papules, hyperwrinkling and sometimes pruritus or pain after water immersion. Its frequency in the general population is unknown. About 40 cases have been reported to date, including some among patients with cystic fibrosis (CF) or CF heterozygotes. OBJECTIVES: To determine the frequency of APPK among patients with CF. METHODS: Twenty-seven patients from the Centre of Competence on Cystic Fibrosis of Roscoff were examined by a dermatologist after immersion of the palms in water for 2-3 min. RESULTS: The frequency of APPK was 41% (11 of 27 patients). Some patients had not previously noticed the lesions. The frequency was higher among inpatients than outpatients. We suspect that occlusion (caused by the gloves worn by inpatients) can explain this difference. The number of patients included in this study is not sufficient to draw any conclusions concerning the type of CF mutation and its impact on the frequency of APPK. CONCLUSIONS: APPK is frequent among patients with CF and, thus, should be considered a sign of CF. APPK is underdiagnosed because physicians usually do not look for it. CF screening should be considered for any patient presenting with these symptoms, followed by genetic counselling if necessary.