Okay kiddo, so you know how sometimes people get colored spots on their skin? Well, sometimes those spots are called pigmented purpuric dermatosis.
Pigmented means that the spots have color, like red, brown, or purple. Purpuric means that the spots are caused by blood leaking out of tiny blood vessels in the skin.
Dermatosis means that the condition affects the skin. Basically, what happens is that the blood leaks out of these tiny blood vessels and causes little bruises under the skin. That's why the spots have color - they're like little bruises!
Pigmented purpuric dermatosis is not dangerous and doesn't cause any health problems, but it can be a bit itchy or tender. It usually only affects a small area of the skin, and can happen to anyone, but it's more common in adults.
So, that's what pigmented purpuric dermatosis is - just colored spots caused by little bruises under the skin. Simple, right?