Itchy skin with red spots on the outside of the penis for circumcision, the skin covering the outside of the penis are called the foreskin, when the occurrence of relevant pathogenic infections or the presence of non-infectious factors, can appear local itching, redness and swelling. First, circumcision, prepuce, etc., can lead to localized inflammation. This inflammation belongs to the foreskin scale long-term chronic stimulation, can be accompanied by localized swelling or accompanied by erosion, oozing and other changes, physical examination can be seen in the presence of more dirt or foreskin scale. Second, when there is a bacterial, fungal, trichomonas infection, there can be itchy skin with red spots, can be accompanied by increased local secretions, such as milky white secretions or cheese-like secretions, can be accompanied by localized vesicles, or localized erythema and other changes, need to carry out the relevant pathogenicity testing to confirm the diagnosis. Third, the skin allergy, such as local contact allergy, common contact with condoms can lead to allergy, can also be seen in the systemic allergic reaction local performance. This time, except for the penis skin itching, red, can also be accompanied by other parts of the body similar red spots or itching and other symptoms, need to carry out the relevant allergens test to confirm the diagnosis.