Small red blood spots on the skin may be caused by local capillary dilation or damage due to allergies, infections and other factors, or may be triggered by systemic diseases or hematologic disorders. Patients are advised to observe for a few days whether the red dots are eliminated, and if they persist, it is recommended to consult a dermatologist. Clinically common in the following cases: I. Types of diseases: 1. Allergic dermatitis: mostly caused by contact with allergens, lesions are mostly confined to the contact location. Typical lesions are erythematous with clear borders, lesion status is related to the contact, and the initial performance looks like red blood spots; 2. Eczema: this disease is an inflammation of the superficial dermis and epidermis caused by a variety of internal and external factors, often symmetrically distributed. Clinical acute phase lesions are mainly erythematous, papular, pinpoint to corn size, looks like red dots, with a tendency to exude. The chronic phase is dominated by mossy lesions, often fused into patches, the boundaries are not clear, easy to recur, itching is intense; 3, purpura: the body due to the immune system, blood system function abnormalities, resulting in blood escape under the skin, mucous membrane, the patient’s skin can be seen petechiae petechiae. The disease is often preceded by prodromal symptoms such as upper respiratory tract infections, followed by red papules, which are pinpoint to soybean-sized red dots. Prevalent in the lower extremities, mainly on the extensor side of the calf; 4, insect bite dermatitis: the more toxic mosquito bites, can appear on the skin red blood spots, papules or petechiae, conscious itching. Second, treatment measures: 1, allergic dermatitis, eczema: can use tacrolimus ointment, pimecrolimus cream, etc., if necessary, choose short-term use of glucocorticoids, also can choose phototherapy; 2, purpura: mainly for the primary disease treatment, if it is caused by the immune system abnormalities, such as idiopathic thrombocytopenic purpura, may need to use immunosuppressants for treatment. Some purpura patients bleeding tendency is more serious, but also need to take hemostatic drugs to control; 3, insect bite dermatitis: various mosquito bites should be promptly removed from the allergic factors, disinfection can be topical 0.05% Dinaide cream, flufenamic acid butyl ointment, glyburide lotion and mupirocin ointment for treatment. If necessary, antihistamines such as loratadine and cetirizine can also be administered internally. In cases of generalized lesions and severe allergy, oral prednisone can also be given for a short period of time.