The Study Of Application Of Novel Instruments Forphototesting On Chronic Actinic Dermatitis

OBJECTIVE:Chronic actinic dermatitis(CAD) is an immunologically mediated photodermatosis characterized by pruritic eczematous lesions of sun-exposed areas. The most common action spectrum for CAD is UVB plus UVA, or UVB or UVA alone(12%–25%). Previously the monochromator or solar simulator was available for phototesting, which was bulky, expensive and hard to maintain. In this study, we first used novel equipments(LED devices and Durham tester existed already) for phototesting on CAD. CAD patients were recruited in order to set up the action spectrum and investigate the better medical therapy. METHODS:1?Minimal erythema doses(MED)of UVB and UVA were measured by using novel equipments(LED device at 365 nm,410nm,460 nm and Durham tester at 311nm). Thirty-six healthy volunteers were involved in the study. Erythema reaction was read 24 hours later.2?Minimal erythema doses(MED)of UVB and UVA were measured by using novel equipments(LED device at 365 nm,410nm,460 nm and Durham tester at 311nm). Sixty-four patients with CAD were involved in the study. Erythema reaction was read 24 hours later.3?Fifteen CAD patients with severe clinical manifestation were recruited and treated with hydroxychloroquine or thalidomide randomly(7 CAD patients treated by hydroxychloroquine and 8 CAD patients treated by thalidomide), clinical manifestations were recorded in details; Phototesting before and after medical treatment was performed. RESULTS:Under the tested dosage of UVA(36J/cm2), none of the healthy volunteers showed positive erythema reaction, while erythema reaction can be detected in 24 CAD patients(37.5%).For UVB testing, MED of CAD patients were significantly lower than those of normal persons(P<0.01). 7 patients showed an increase in MED-UVA after thalidomide treatment, while none of the patients showed change of MED-UVA after hydroxychloroquine treatment. And for MED-UVB, both two groups showed no significant change. CONCLUSION:Novel instruments for phototesting on diagnosis and management of CAD can be practised, characterised by its availability, portability and low cost. Furthermore, thalidomide may be a good choice for treatment of recalcitrant chronic actinic dermatitis.