Continuum of light sensitivity in atopic dermatitis: A retrospective analysis of 139 cases in Scotland.

Abstract

Previous reports have characterized photosensitivity in atopic dermatitis (AD), but with differences in terminology and criteria. This study aims to assess outcomes in 139 patients with AD referred for photodiagnostic testing and to establish diagnostic criteria for photosensitivity in AD. Clinical and photodiagnostic data were reviewed, categorizing photosensitivity into photoexacerbated AD, photosensitive AD, and chronic actinic dermatitis. Of the patient cohort, the mean age was 42.6 ± 16.7 years, and 61.9% were men. In total, 51.1% of the patients with photoexacerbated AD had normal monochromator phototesting, and 7.9% of the patients with photosensitive AD displayed slight-to-moderate ultraviolet (UV)-A sensitivity (≥30% of normal minimal erythema dose [MED]) and mostly normal or slightly reduced UV-B MEDs (≥80% of normal MED). Conversely, 41% of the patients had chronic actinic dermatitis, and 93% of this group demonstrated significant UV-B sensitivity, with very low UV-B MEDs (<80% of normal MED) and/or very low UV-A MEDs (<30% of normal MED). No significant differences in sex, age, or skin phototype were observed between the groups. Serial phototesting revealed changes in photosensitivity status over time in 8 patients. A small sample size and retrospective design. This study highlights the heterogeneity of photosensitivity patterns in patients with AD and the importance of follow-up assessments due to potential shifts in disease spectrum over time.