Red blood spots with pinpoint size on the body may be allergic purpura, or insect bite dermatitis, contact dermatitis and other diseases. 1. Anaphylactic purpura: this disease is a vascular metamorphic reaction disease, mainly allergens lead to increased vascular fragility and vascular permeability, which can affect the small blood vessels in many parts of the body, thus showing pinpoint red blood spots on the body, and may be accompanied by abdominal distension, nausea and other symptoms. 2. Insect bite dermatitis: common in hot summer, especially outdoor mosquitoes, if accidentally bitten by mosquitoes, may lead to the bite of the skin pinpoint red blood spots, may also be accompanied by obvious itching, pain and other symptoms. 3. Contact dermatitis: skin in contact with chemical agents, rubber products, detergents and other substances, may cause an allergic reaction leading to contact dermatitis, may lead to contact with the skin at the site of erythema, pimples, there may also be a pinpoint size of the bleeding points, blood blisters, etc., accompanied by itching, burning pain and other symptoms. It is recommended that patients with pinpoint-sized red blood spots go to a regular hospital in a timely manner, after a clear diagnosis, under the guidance of the doctor to give targeted treatment.