Subcutaneous nodules can be seen in AIDS, but not all subcutaneous nodules are seen in AIDS and may be symptoms of diseases such as lipoma and rheumatoid arthritis. Subcutaneous nodules may appear after skin infections caused by AIDS, which leads to a decrease in the body’s immune system and the attack of viruses, bacteria, and other pathogens. However, the formation of subcutaneous nodules is due to a variety of reasons that are not unique to AIDS and are usually associated with tissue proliferation, inflammatory infiltration, and metabolite accumulation. If the subcutaneous nodules are soft, well defined, and not accompanied by other uncomfortable symptoms, they are usually considered to be benign proliferative diseases such as lipomas and dermatofibromas. Subcutaneous nodules in the area of hair follicles may be sebaceous cysts formed after infection by folliculitis, acne or other skin diseases. If accompanied by joint pain, swelling, morning stiffness and other symptoms, may be rheumatoid arthritis caused by rheumatoid nodules. It is recommended to seek prompt medical attention from a medical professional to find out the exact cause of the subcutaneous nodules.