Erythrokeratoderma variabilis.

A 51-year-old woman presented with well-demarcated, erythematous patches and hyperkeratotic plaques that were arranged symmetrically on the upper extremities. Her skin lesions first appeared at age 17, and there was a family history of similar skin lesions in nine of her eleven siblings. Physical and emotional stress increased the number and intensity of her skin lesions as did chocolate. The distribution of lesions on her skin had changed over time; however, the lesions consistently appeared symmetrically and favored the extensor surfaces of her extremities. The physical examination, histopathologic findings, and family history were consistent with a diagnosis of erythrokeratoderma variabilis (EKV), a rare genodermatosis caused by various mutations in connexin genes. Connexin genes code for proteins that form intercellular channels called gap junctions that allow for transport and signaling between neighboring cells in the epidermis. Mutations in connexin-31 and connexin-30.3 are known to cause the EKV phenotype, which presents as erythematous patches and hyperkeratotic plaques. Studies to examine the effectiveness of treatment of EKV have not been performed; however, several case reports suggest the efficacy of oral retinoids. After 4 months of acitretin 25 mg per day, our patient experienced near complete clearance of her skin lesions.