Preliminary Study On Chronic Actinic Dermatitis In Clinical And Skin Photoimmunological Aspects

Chronic actinic dermatitis is one of the most frequently encountered photodermatoses in patients who are older than 50 years of age and have often extreme sensitivity to the sunlight. In this paper, based on the clinical retrospective analysis of cases of CAD, we investigated the clinical features, photobiological features, inducing factors of attack, the application and efficacy of sunscreens and some characters of the skin photoimmunology in patients with chronic actinic dermatitis. This study was divided into four parts.Part â… : Clinical analysis of 86 cases of chronic actinic dermatitisClinical data from 86 cases of chronic actinic dermatitis were analyzed retrospectively. With metal halide lamp a lowered ultraviolet-A (UVA) minimal erythema dose (MED) was found in 95.3% of patients, ranging from 0.2J/cm~2 to 15J/cm~2 and a lowered ultraviolet-B (UVB) MED was found in 77.9% of patients, ranging from 4mJ/cm~2 to 20mJ/cm~2. Photoallergens were confirmed in 14 patients by photopatch test. Therapies with ultraviolet light and photoallergens avoidance, topical or systemic corticosteroids were effective in most cases. Spontaneous remission was found in some patients after repeated relapses. We could draw the conclusions as 1) diagnosis of chronic actinic dermatitis depends mainly on the clinical features and results of photobiological tests; 2) appropriate ultraviolet light and photoallergens avoidance are important in the prevention and the cure of the disease.Part â…¡: Determination of action spectrum, of patch and photopatch tests in patients with chronic actinic dermatitisThe objective of this part is to confirm the roles of the action spectrum of CAD and the related photoallergens and contact allergens in the pathogenesis of CAD. The MEDs for UVA and UVB in patients with CAD were measured by SUV1000 type ultraviolet simulator. Patch and photopatch tests were performed on patients with CAD, polymorphous light eruption (PLE) and chronic craniofacial eczema, according to the regular patch procedure and the standard procedure of photopatch test recommended by the British Photodermatology Group (BPG). Of the cases tested, a lowered UVA-MED was found in 89.41%, ranging from 1J/cm~2 to 20 J/cm~2 and a lowered UVB-MED was found in 69.41%, ranging from 2.8mJ/cm~2 to 20mJ/cm~2. To be sensitive to UVA alone was found in 30.58%, to UVB alone in 10.59%. The probable normal value for both UVA and UVB-MED and the changeable action spectrum as well were revealed in part of CAD cases by the results of the MED reevaluation. Positive patch and photopatch reactions in patients with CAD appeared to be...