What can cause the top of my nine yr olds penis to itch. no redness and dr found no symptoms like eczema. botched circumsision?

Itchy penis: If there is no rash associated with a localized area of itching on the penis, it is unlikely to be related to a botched circumcision. It may be a localized peripheral neuropathy ( a injury or other problem involving the nerves that innervate the base of the penis) or possibly a psychosomatic complaint.

Contact dermatitis?: Sometimes a nine year old is not the best at toilet hygiene and after urination there may be some urine present on and around the glans. Urine is irritating and cause itching, or later redness, rash in the area. Also the moist, warm environment make things even worse. Circumcision issues is unlikely as cause for the itching. Use some baby wipes after peeing for a week and see if that helps.