Chronic actinic dermatitis in Asian skin: a Singaporean experience

Background/purpose: To study the characteristics of chronic actinic dermatitis (CAD) in a heterogeneous group of Singaporean patients. Methods: The photobiologicial features of all patients phototested and diagnosed with CAD from January 2005 to December 2009 were examined retrospectively. Results: Fifty-eight patients were diagnosed as having CAD. The mean age at diagnosis was 62 years (range 35–83). Forty-one were (70.7%) Chinese, six (10.3%) Indians, eight (13.8%) Malays, and three (5.2%) Others. Forty-seven were (81.0%) male and 11 (19.0%) were female. Forty-nine (84.5%) had Fitzpatrick skin phototype IV and nine (15.5%) had phototype V. Three of 26 (11.5%) tested for human immunodeficiency virus were positive. The face, neck, and forearms were most commonly affected. Thirty-two patients (55.2%) had reduced minimal erythema dose (MED) to both ultraviolet B (UVB)and ultraviolet A (UVA), 23 patients (39.7%) had lowered MED to UVB only, while three (5.1%) had reduced MED to UVA only. Patients were followed up for a mean of 16.8 months. All were treated with photoprotection and topical steroids; however, a few required oral immunosuppression with partial improvement. Conclusion: In Singapore, CAD was seen more commonly in elderly Chinese males of Fitzpatrick skin phototype IV. Reduced MED to both UVB and UVA was the most common phototest finding.