Trauma is considered a mechanical, physical injury to the skin. This includes wounds of the upper skin layers such as scratches and scrapes, wounds of the lower skin layers, such as cuts and tears.
Small superficial trauma normally only causes reddening of the skin, and in rare cases, minor bleeding, which is seen in form of a hematoma (also known as a "hickey"). Depending on the depth of the lesion, if the skin layers are separated, bleeding or serous discharge occurs. Skin trauma may be covered by the animal’s coat and go undiscovered. Injuries of the skin are more readily seen on the dog’s limbs, underbelly or chest. Caution needs to be taken as skin cuts can become infected and produce pus. When the healing process starts, the lesion is covered by a crust - or - the formation of a scab. This regenerative tissue can be sometimes mistaken for a lump or small tumor.
The most common skin trauma in dogs is caused through bites after fights with other dogs. Furthermore, trauma may be caused by accidents or as random injuries while playing or running.
Small injuries to the skin may be left untreated. As a rule of thump: any wounds larger then 1/2 inch (appx. 1 cm) have to be cleaned and stitched. Once scabs have formed they must not be removed, as this will impair the healing process.
If a wound is bleeding heavily, a towel or cotton swab should be pressed onto the lesion, and may be stopped by applying some additional gauze. The animal should then be immediately taken to a veterinarian practice or clinic to be checked by a veterinarian.