Transient aquagenic palmar hyperwrinkling (TAPH) is a rarely reported cutaneous condition clinically characterized by swelling and hyperwrinkling of the palms, and associated with burning sensations after briefly immersing the hands in water. Upon the withdrawal of water, the symptoms rapidly disappear. We report on a 10-year-old boy with type I diabetes, who developed the typical symptoms of TAPH concomitantly with the onset of palmar hyperhidrosis. Determination of the sodium chloride concentration of the sweat revealed elevated levels. Subsequent screening for the most common mutations of the gene responsible for cystic fibrosis (CF) was negative. Review of the literature shows that TAPH may develop in conditions of increased water absorption due to an increased sweat quantity, such as hyperhidrosis, or an increased sweat electrolyte concentration, such as CF. In the majority of reported cases TAPH has been associated with CF; therefore, it is a cutaneous sign, which should be recognized by dermatologists, and patients should be referred for evaluation of the sodium chloride concentration of the sweat.