Actinic purpura 當血液滲入皮膚真皮層時就會發生。發生此情況是因為皮膚變薄、血管脆弱，尤其是長期暴露在陽光下的老年人更易受影響。 Actinic purpura results from the extravasation of blood into the dermis. This phenomenon is due to the skin atrophy and fragility of the blood vessels in elderly individuals, which is exacerbated by chronic sun exposure.
○ 治療
大多數紫斑約 7 天後自行消退。若紫斑在無明顯原因的情況下反覆出現，應就醫並接受血液檢查，以評估是否有凝血功能障礙。