Red, swollen, itchy and painful hands may be caused by eczema, cold sore or urticaria. 1. eczema: eczema is a relatively common skin disease, the cause is not clear, and may be genetic, immune function abnormalities, endocrine abnormalities, as well as dietary factors, environmental factors and chronic diseases, etc., the main symptom is that the affected area of the skin will be red, swollen, itchy and painful phenomenon, there may also be pimples as well as pimples and other manifestations. 2. sweating herpes: sweating herpes may be related to environmental factors, genetic factors and personal factors, preferably in the palm of the hand, the main symptom is that there will be localized deep herpes, accompanied by itching and discomfort. 3. urticaria: urticaria is also relatively common in life, may be related to dietary factors, infectious factors, genetic factors and immune abnormalities, the onset of the site will usually be red, swollen, itchy and painful symptoms, there may also be a headache, shortness of breath, palpitations and other manifestations. Hands red, swollen, itchy and painful to actively go to the regular hospital, a clear diagnosis, and then targeted treatment, so as not to delay the condition.