Redness and swelling of penile veins can be caused by penile trauma, circumcision, allergy and other factors. 1. Penile trauma: when the penis suffers a blow from external force, resulting in localized damage, the veins will become red, swollen and may be accompanied by severe pain. 2. PAPPICULOIDITIS: Long time not pay attention to the hygiene of the lower body, easily induced by PAPPICULOIDITIS, which can lead to localized redness and swelling of the veins, which may be accompanied by itching, and in severe cases, it can be broken and oozing. 3. Allergy: When there is a localized allergic reaction in the penis, it will also make the local veins red and swollen, and may be accompanied by intense itching. Redness and swelling of the penile veins indicate the presence of abnormalities that need to be alerted, and it is recommended that medical examination and treatment be carried out to avoid continued aggravation of the lesions.