Sunburn
The skin can develop petechial rashes or red spots after intense exposure to the sun. This rare allergic condition is known as sunburn purpura or photo localized purpura which usually results from a condition known as polymorphous light eruption (PLE).
This rare condition occurs when ultraviolet rays from the sun cause damage to the walls of the superficial blood vessels under the skin. It causes the blood vessels to dilate and thin out, causing the vascular walls to break and collapse, resulting in bleeding and bruising. The bruising and blood leaks from the broken blood vessels then become visible through the overlying epidermis, resulting in blood spots on the skin. These blood spots resulting from sunburn purpura may turn into slight, brown discoloration of the skin or scarring, which can be uncomfortable and unsightly after the bruising fades.
Like the petechial rashes resulting from physical trauma, solar petechial rashes aren’t dangerous. However, it fades on its own within one to three weeks, regardless of how acute the skin changes have been.
