Clinical characteristics of adult-onset actinic prurigo in Asians: a case series.

Background: Actinic prurigo (AP) is a chronic, pruritic skin condition caused by an abnormal reaction to sunlight.

Aims: The aim of this study is to determine the clinical characteristics of AP in patients attending the National Skin Centre, Singapore, from 1 st January 1999 to 30 th June 2008.

Methods: Cases of AP diagnosed from 1 st January 1999 to 30 th June 2008 were retrieved from the center's electronic medical records and analyzed.

Results: A total of 11 patients were diagnosed with AP. The mean age at diagnosis was 52 years. There were 9 (82%) Chinese and 2 (18%) Malay patients. Nine (82%) were male and 2 (18%) were female. The most commonly affected areas were the face, forearms, and hands (72%). Phototesting showed reduced minimal erythema dose (MED) to ultraviolet A (UVA) in 5 (46%) patients, both UVA and ultraviolet B (UVB) in 4 (36%) patients and UVB in 1 (9%) patient. Seven (64%) patients reported partial improvement after treatment with a combination of topical corticosteroids and sunscreens. Four (36%) patients received systemic therapy with partial response.

Conclusion: Adult-onset AP is more common in the Asian population, with a male predominance. The face, forearms, and hands are the most commonly affected areas. The absence of mucosal involvement is also a distinguishing feature between the Asian and Caucasian population. Close to half of the patients have reduced MED to UVA on phototesting. The prognosis for AP is poor as it tends to run a chronic course with suboptimal response to treatment.