Waking up to see a sudden, dark spot on your child’s foot can be frightening.
When that spot looks swollen, deep in color, and seems to cause pain or difficulty moving the foot, worry comes naturally. Many parents immediately fear the worst, especially when there was no obvious injury the day before.
raph – under_first_paragraph –>
In many cases, what you are seeing may be a blood blister — a condition that often looks alarming but is usually manageable with proper care and attention. Understanding what a blood blister is, why it can appear overnight, and how to respond safely can help you stay calm while protecting your child’s well-being.
That said, pain and limited movement should always be taken seriously, especially in children. Knowing when home care is enough and when professional evaluation is needed is essential.
What Is a Blood Blister?
A blood blister forms when small blood vessels just beneath the skin break, but the outer layer of skin remains intact. Blood becomes trapped under the surface, creating a raised area that looks dark red, purple, or even black.
Unlike clear blisters filled with fluid, blood blisters appear darker because they contain blood rather than clear serum.
They can appear suddenly and may seem to come “out of nowhere,” especially when the cause was pressure rather than a visible injury.
Blood blisters most commonly appear on:
The soles of the feet
Toes
Fingers and palms
Inside the mouth, such as on the cheek or tongue
On the foot, they often develop in areas that bear weight or experience friction.
