Hi,
Itching inside the end of penis could be due to infection. Most of the times it is acquired by sexual act.
A careful examination of the glans and the prepuce has to be done to look for the nature of lesions. The lesions vary depending on the type of infections you have got.
Diabetes mellitus also causes itching of the end of penis by predisposing to fungal and other infections.
Doctor
MD, DM.