Photosensitive and phototriggered pityriasis rubra pilaris

We report a 59-year-old man with photosensitive and photodistributed pityriasis rubra pilaris. The phototriggering of the lesions was obtained by the iterative polychromatic phototest (3 times the minimal erythema dose (MED) on 3 consecutive days) and was also observed on the supra MED sites, which began the 10th day and persisted several months. Our results are comparable to those already obtained in photosensitive psoriasis, which helped us to identify the clinical similarities of photosensitivity in these two instances of dermatosis.