Understanding Blood Blisters: Causes, Treatment, and Prevention

Encountering a blood blister for the first time can be startling. These dark red or purplish bubbles beneath the skin often seem to appear without warning. While they are generally harmless, they can cause significant discomfort and, in some cases, serve as a signal for an underlying health issue. Understanding what these blisters are and how to manage them is essential for proper healing and knowing when to seek professional medical advice.

What is a Blood Blister?

A blood blister forms when tiny blood vessels, known as capillaries, break beneath the skin while the surface layer remains intact. The blood becomes trapped, creating a raised, fluid-filled spot that is noticeably darker—maroon, deep red, or purple—than a standard clear friction blister.