Actinic purpura: This is a benign change in the skin caused by sun damage to the deeper layer of skin known as the dermis. It appears as patchy purplish blotches (bruises) on the skin. It is most common in elderly people after a minor trauma to the skin. Actinic purpura usually occurs on the forearms or backs of the hands and lasts for 1-3 weeks. It is also known as senile purpura.
Schwartz, Robert A. "Actinic Purpura." Apr. 28, 2020. Medscape.com. <https://emedicine.medscape.com/article/1087008-overview>.