关键词: 慢性光化性皮炎, 最小红斑量, 光斑贴试验

Abstract: Objective: To investigate the minimal erythema dose（MED）and photopatch test in patients with chronic actinic dermatitis
（CAD） in Dali region, aiming to explore the differences in the pathogenic spectrum of CAD patients and potential sensitizing
substances. Methods: MED was measured using a solar simulator in 25 CAD patients and 20 healthy volunteers. The photopatch test
was conducted using the RIMIN standard photopatch test reagent kit. Results: The long-wave ultraviolet minimal erythema dose（ UVAMED）
for CAD patients was 25.63 J/cm2, and the medium-wave ultraviolet minimal erythema dose（UVB-MED） was 20.56 mJ/cm2. The
UVA-MED for healthy volunteers was 49.92 J/cm2, and the UVB-MED was 38.80 mJ/cm2. The MED values in CAD patients were
significantly lower compared to healthy volunteers（P<0.05）. The positive rate of photopatch test in CAD patients was 44%, with
common photoallergens including hexyl 2-（4-diethylamino-2-hydroxybenzoyl）benzoate, promethazine hydrochloride, and 2-hydroxy-
4-methoxybenzophenone. Conclusion: CAD patients are sensitive to both UVA and UVB, and exposure to photocontact allergens may
be an inducing factor for CAD.

Key words: chronic actinic dermatitis, minimum erythema dose, photopatch test