A traumatic tattoo is when foreign bodies become forcibly embedded in the dermis and create a permanent tattoo. Such particles may include fireworks, sand, metal, glass, gunpowder, asphalt, dust, petroleum products, and graphite from pencil point injuries. Traumatic abrasions (such as after a road accident) are a more frequent cause of traumatic tattoos than explosions. Minor trauma, such as from penetration of a pencil through the epidermis, may also be responsible.

Particles become trapped beneath healing dermis and epidermis. In explosion injury, particles may also become trapped behind a collapsed entry wound. Body location of the tattoo depends on where the trauma occurred. Lesions vary widely in size and shape depending on the causative injury, and are usually blue, gray, or black.