Circumscribed Palmar Hypokeratosis

A 65-year-old otherwise healthy female patient presented with an atrophic, asymptomatic, coin-sized plaque on the palm of her right hand. Three years ago, she had initially noticed an erythema following an insect bite while traveling through Laos which showed a tendency to grow slowly over time. Visits to her primary care physician and specialists in tropical medicine and endocrinology did not lead to a diagnosis. A biopsy obtained from the margin of the lesion showed a step-like flattening of the otherwise orthokeratotic stratum corneum with fraying at the transition. The picture is that of circumscribed palmar hypokeratosis. This epidermal differentiation disorder mainly affects middle-aged and older women. The solitary, asymptomatic, atrophic plaque with punched-out appearance varies in size from a few millimeters to three centimeters. Its etiopathogenesis is unknown. An association with an internal disease or reactive events, such as insect bites, has not been described. Globally, 110 cases of the disease, which was first described in 2002, have been published. Being asymptomatic and benign in nature, circumscribed palmar hypokeratosis is likely to be significantly underdiagnosed. Over the course of the disease, growth and erythema subside. No treatment is required.

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Dr. med. Katharina Meier, Dr. med. Rose K. C. Moritz, Dr. med. Amrei Dilling, Department of Dermatology, Venereology and Allergology, Charité-Universitätsmedizin Berlin,[e-mail]

Conflict of interest: The authors declare no conflict of interest.

Translated from the original German by Ralf Thoene, M.D.

Cite this as: Meier K, Moritz RKC, Dilling A: Circumscribed palmar hypokeratosis. Dtsch Arztebl Int 2024; 121: 613. DOI: 10.3238/arztebl.m2023.0241