Diagnostic dilemma: A rare condition caused a man to get 'scales' on his hands whenever he washed them
A man's rare condition caused "excessive wrinkling" in his hands which spread to his wrists and elbows.
White bumps and growths appeared on the back of the man's hands after being being submerged in water. (Image credit: Image courtesy of JAMA NetworkⓇ. © 2025 American Medical Association.)
The patient: A man in his 20s in China
The symptoms: A man went to the dermatology department of a hospital after experiencing an array of symptoms for about three years. When he submerged his hands in water, such as during hand-washing, the skin on the back of the man's hands thickened and became overly wrinkly, with white bumps and growths appearing.
The man had previously sought treatment at his local clinic, where he was diagnosed with chronic eczema — which causes skin to become dry, thick and itchy — and prescribed a strong retinoid ointment, which he used intermittently. However, this treatment didn't work, and his symptoms gradually worsened. His wrists and elbows had also started to develop the skin lesions over the 1.5 years prior to the hospital visit.
The patient had no family history of similar skin conditions and did not experience excessive sweating or have any allergies, and he had never injured his hands. The man attributed the worsening of his condition to him washing his hands more frequently during the COVID-19 pandemic, the doctors wrote in the report of the case.
What happened next: During a physical examination at the hospital, the man's hands were immersed in water for 10 minutes, immediately causing the tops of his hands, fingers and wrists to grow red, scaly and wrinkly with white lesions. Notably, the "excessive wrinkling" and bumps ended in a straight line on the sides of his hands, leaving his palms unaffected.
The doctors took biopsies from the white bumps on his right hand, which revealed that the sweat ducts in the top layer of skin had widened and contained more sweat glands than normal. The results also showed he had hyperkeratosis, meaning his body was producing too much of the protein keratin, causing the outer layer of skin to thicken.
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The medical team wrote that "the patient's clinical process was quite interesting," because the symptoms of the skin condition appeared only after his hands were immersed in water and all symptoms disappeared around 30 minutes after his hands dried.
