To determine the frequency and reproducibility of standardized photoprovocation in patients with cutaneous lupus erythematosus (CLE) and report our long-term experience.
Photoprovocation using a standardized protocol was evaluated retrospectively in 566 patients. A diagnosis of CLE was clinically and/or histologically confirmed in 431 patients, and 315 patients with polymorphic light eruption (PLE) were additionally included as controls. Data were statistically analyzed using an SPSS database.
A total of 61.7% of the 431 CLE patients exhibited a positive photoprovocation, with a significantly longer latency period for the development of skin lesions after ultraviolet (UV) A and/or UVB irradiation than PLE patients (P < 0.001). The frequency of positive photoprovocation varied among the CLE subtypes, and intermittent CLE was the most photosensitive disease entity (74.8%). Subsequent photoprovocation in 35 patients demonstrated that CLE patients with an initial positive result exhibited a significantly higher frequency of a positive photoprovocation at a later time point (P = 0.013). However, an initial positive photoprovocation did not definitively predict a positive reaction at a later time point. Moreover, patient history of photosensitivity was not a predictor for the photoprovocation outcome.
Standardized photoprovocation is a useful tool to reproducibly induce skin lesions and objectively evaluate photosensitivity in patients with CLE. These data further suggest that the reaction to UV light may change during the course of this heterogeneous disease and that photosensitivity should not be excluded in patients with a negative history of photosensitivity.