[A case report of progressive symmetric erythrokeratodermia and a review of progressive erythrokeratodermia in Japan].

The patient is a 5-year-old boy. There was no family history of the similar skin eruptions. The erythema with scales appeared on his head, face and neck at 1 month of birth. The erythematous hyperkeratotic plaques spread symmetrically. There was no follicular components. The eruption was chronic and persistent. In histopathology, hyperkeratosis with focal parakeratosis, acanthosis and intact granular layer were observed. In electron microscopy, a large number of mitochondria that frequently appeared to be swollen and lipidlike vacuoles in corneocytes were observed. On account of the features, we diagnosed this case as progressive symmetric erythrokeratodermia (PSE). PSE is a rare disease, and besides, it is difficult to define PSE because of contradictions in existing literatures, the variability of clinical expression and the lack of histologic, hereditary, and biochemical criteria. Nearly 70 cases were diagnosed as PSE and its variants in Japan i.e. 4 cases with PSE, 8 cases with progressive erythrokeratodermia, and 58 cases with Asahi-Ijiri disease and its variants. However, only 2 cases diagnosed as PSE and 4 cases nominated as others satisfied the recently established criteria by Ruiz-Maldonado, et al. In this paper, reported cases of PSE and its variants were reviewed and reassessed.