Shaving is one of the most common causes. Using an old or dull razor, or skipping shaving cream, can lead to razor burn, which shows up as dark marks. Razor burn can also cause folliculitis, leading to ingrown hairs that appear as small black dots, and when there are many of them, the legs can take on that speckled, strawberry-like pattern. Clogged pores are another factor: some people are simply born with larger pores and thicker body hair on their legs, and when those pores get clogged, the trapped oil oxidizes and turns black when exposed to air. These clogged pores are called comedones. When many are present, they create the same visual effect. Folliculitis, meaning inflamed or infected hair follicles after shaving, waxing, or other hair removal, is a third contributing cause, since the open follicle becomes exposed to bacteria, yeast, or fungus and can develop a darker appearance as it struggles to heal.