The natural history of chronic actinic dermatitis

Objective: To determine the prognosis for resolution of abnormal cutaneous photosensitivity in patients with chronic actinic dermatitis (also known as the photosensitivity dermatitis and actinic reticuloid syndrome). Design: Historical cohort study involving follow-up of patients for up to 2 4 years from diagnosis. Setting: A Scottish tertiary referral center for investigation of photoderm atosis. Patients: One hundred seventy-eight patients with chronic actinic dermatiti s, 62% of a cohort of 285 living patients identified in the Photobiology Un it database. Interventions: Recall for repeated clinical assessment and monochromator ph ototesting. All patients underwent patch testing when initially assessed; t his was repeated at follow-up in a subgroup of patients. Main Outcome Measures: Resolution of abnormal photosensitivity, defined as clinical resolution and return of phototest responses to within normal popu lation limits. In addition, possible prognostic factors for resolution of p hotosensitivity were examined. Results: The probability of abnormal photosensitivity resolving by 10 years from diagnosis is 1 in 5. Particularly severe abnormal UV-B photosensitivi ty (minimal erythema dose at 305 +/- 5 nm half-maximum bandwidth, less than or equal to 5.6 mJ . cm(-2)) and the identification of separate contact al lergens in 2 or more patch test batteries are predictors of a poorer progno sis for resolution. Loss of contact allergies was not associated with a dif ferent prognosis for photosensitivity resolution. Our findings probably und erestimate the probability of resolution, as those referred to a tertiary r eferral center and willing to attend for follow-up may include a disproport ionate number of severely affected patients. Conclusions: Newly diagnosed patients can be told that most of them will im prove with appropriate UV/visible light and allergen avoidance and that the re is hope that their photosensitivity will completely resolve.