Clinicophotobiological Characterization of Photoaggravated Atopic Dermatitis

Photoaggravated atopic dermatitis (PAD) is estimated to affect 1.4% to 16% of patients with AD but remains poorly characterized with limited published data.

To provide detailed clinical and photobiological characterization of PAD.

This case series study used cross-sectional data collected from 120 consecutive patients diagnosed with PAD from January 2015 to October 2019 at a tertiary center referral unit for photobiology.

Routinely collected standardized clinical and photobiological data were analyzed using descriptive statistics, and regression analysis explored associations between demographic and clinical data.

Of 869 patients who underwent photoinvestigation, 120 (14%) were diagnosed with PAD (69 female [58%]; median age, 45 [IQR, 31-61] years; range, 5-83 years; skin phototypes [SPTs] I-VI). Of these patients, 104 (87%) were adults. All patients had a history of AD, and most (62 of 104 [60%]) presented with sunlight-provoked or photodistributed eczema; median age at photosensitivity onset was 37 years (range, 1-72 years). Past-year Dermatology Life Quality Index score was greater than 10 for 80 of 103 adults (78%), and 82 of 119 (69%) had vitamin D (25-hydroxyvitamin D) level insufficiency or deficiency (<20 ng/mL; to convert ng/mL to nmol/L, multiply by 2.496). Broadband UV radiation provocation test results were positive for 112 patients (93%). In 28 patients (23%) with abnormal monochromator phototest findings, sensitivity occurred to UV-A, UV-B, and/or visible light, and UV-A of 350 ± 10 nm was the most prevalent wavelength. Photopatch test reactions were positive for 18 patients (15%). Patients with SPTs V to VI (31 [26%]) vs SPTs I to IV (89 [74%]) were younger at photosensitivity onset (median age, 24 years [IQR, 15-37 years] vs 40 years [IQR, 25-55 years]; P = .003), were more likely to be female (23 [74%] vs 46 [52%]; P = .03), and had a lower vitamin D status and a higher frequency of abnormal monochromator phototest findings.

In this case series study, PAD affected patients with different ages and SPTs and was associated with substantially impaired quality of life. The findings suggest that confirming PAD through phototesting may provide better personalized care for patients through identification of provoking wavelengths, relevant photocontact allergies, and appropriate photoprotection advice.