It actually forms dark skin lesions along blood vessels and lymph nodes, and it can be brown, red, or purple in color. This condition often occurs in the later or next stages of HIV when the T4 cell count is low, and the immune system is weak. When HIV causes a rash in the early stage, it can appear differently for people with different skin tones. In fair-skinned individuals, the rash is usually flushed, discolored, or reddish. For those with dark skin, it may appear dark purplish. The blemishes are flat and may cause mild itching.