The appearance of red blood dots on the skin on the body can be caused by a variety of reasons, commonly due to mosquito bites, or may be a vascular nevus formed after long-term sun exposure, which is generally a normal phenomenon and requires no special treatment. In addition, it may also be related to other disease factors, such as prickly heat, dermatitis, psoriasis, spider nevus, lupus erythematosus, etc. Since this symptom is not specific, if it appears in a large area or affects daily life, it is recommended that patients seek medical attention for a clear diagnosis. 1. prickly heat: it occurs mostly in the hot season and can appear on the skin with red blood dots and itchy sensation. The patient should pay attention to ventilation, keep the lesion area dry and clean, also can be treated with topical mupirocin ointment, fusidic acid cream cream, etc.; 2, dermatitis: common in allergic dermatitis, usually caused by contact with allergens. If the scope of the red blood dots on the skin is not large, you can use the appropriate concentration of boric acid solution, aluminum acetate solution, etc. for cold compresses. If the symptoms are more serious, it is recommended to seek medical attention in a timely manner, and can be treated with oral antihistamines such as cetirizine hydrochloride tablets and betahistine hydrochloride tablets under the guidance of a professional doctor, with glucocorticoids, antibiotics and other combined treatments if necessary; 3. Psoriasis: the disease begins as a red papule with white scales at the top, and if the scales are gently scraped away, you can see dotted bleeding at the bottom. Often distributed in the scalp, limbs and trunk, heavy fingernails and toenails point-like depression, and the nail plate is not flat. Some patients have joint swelling and pain. Mild and moderate psoriasis can be treated with local glucocorticoids and vitamin D drugs, while severe psoriasis mostly needs phototherapy and systemic treatment; 4. spider nevus: mainly manifests as spider-like rashes in the superior vena cava reflux area, head and neck, upper chest and upper limbs, such as red blood dots, which can disappear when pressed on the central area, called “spider nevus”. It is called “spider nevus”. It is mostly seen in chronic liver disease, cirrhosis, etc., and in a few cases in women with ulcer disease and menstrual disorders. If it occurs in female patients during puberty or pregnancy, it is usually normal and can fade away on its own in a few days without special treatment. If it occurs on the face, it will affect the beauty of the face and can be removed by laser treatment. If it is caused by the original disease, the original disease should be treated actively, and the spider nevus can be gradually relieved with the cure of the original disease. 5. Lupus erythematosus: Generally, it shows symmetrical red blood dots with bright red or purple-red color on the exposed parts of the skin, and the surface is smooth and sometimes there are scales. When the disease is in remission, the blood-red dots may fade away, leaving brownish deposits. If the rash is typical, butterfly-shaped erythema may appear on both cheeks and the bridge of the nose. Moreover, most patients have symptoms such as low-grade fever and arthralgia, and some patients may have manifestations of heart, brain, lung and gastrointestinal tract invasion. Clinical treatment is mainly carried out with biological agents such as glucocorticoids, immunosuppressants or complement inhibitors and cytokine inhibitors. In addition, endocrine disorders, urticaria, allergic purpura, senile hemangioma and other factors can lead to the appearance of red blood dots on the patient’s body. If the symptoms are serious, it is recommended to go to the hospital for timely consultation and treatment after clarifying the cause.