Case of acrodermatitis continua of Hallopeau following psoriasis with atypical clinical presentation.

We present a 63-year-old Japanese woman who had clinically unique symmetrical skin rashes on her lower face, inframammary area, back and extremities, with some pustules on the cheeks. Skin biopsy specimens showed typical findings of psoriasis, and Psoriasis Area and Severity Index score was 5.9. After the skin lesions were treated successfully with vitamin D3 ointment, pustules developed on the tips of the fingers and toes, with paronychial and subungual involvement. The pathology of the nail matrix was consistent with pustular psoriasis, and the patient was diagnosed with acrodermatitis continua of Hallopeau (ACH) following psoriasis with an unusual clinical presentation. ACH was well controlled with a low dose of cyclosporin. Our patient is a rare case chronologically affected by two diseases in the same category. We confirmed that ACH is a variant of pustular psoriasis, and believe that the patient could provide another clue to determining the entity of ACH.