Rain Rot - Horseman's News
Rain rot is a skin infection caused by the bacteria Dermatophilus congolensis. Although the bacteria is present in the environment all the time, it requires a moist environment and a break in the skin to develop into the characteristic hard, painful crusts over a horse’s back and rump. These crusts are distinctive not only because of their where they occur on the horse’s body, but also because when removed, hairs stick through scab and look like a mini "paintbrush."