The appearance of small gray spots on the body, there may be purpura, flat warts, hyperpigmentation and other causes. 1. Purpura: allergic purpura, idiopathic thrombocytopenic purpura can cause subcutaneous capillary rupture, may lead to skin bleeding points, skin bruises, so it may lead to the phenomenon of small gray spots on the body. 2. flat warts: is caused by the human papilloma virus infection caused by the skin superfluous organisms, the early stage of the disease may also lead to the appearance of small gray spots on the body. 3. pigmentation: sunlight exposure, local skin inflammation reaction and other reasons, can cause skin pigmentation, will also appear on the body of the small gray spots. The appearance of small gray spots, there may be other reasons, it is recommended to go to the hospital for examination, to clarify the cause of the disease, and follow the doctor’s instructions for treatment.