Extremely itchy penis

You obviously have something causing a considerable irritation to your penis, and, something has inflamed your glans / head of penis.  Can you specify how you maintain your penile hygiene?  Also, have you just started using something in the last few weeks / months that has not been in contact with your penis previously?  This could be anything from a skin cream, lotion, if you are sexually active, lubes, condoms, that kind of thing.  It sounds like you have quite a dermatological reaction going on ....

The feeling of it being irritated when moisture sits on it doesn't sound like a bacteria infection. I would guess that whatever is in the soap your body doesn't like.

Your mention of pre-cum being an irritation is interesting, and an issue I had.  I think you would benefit from putting an exemplary hygiene practice in place.  If something should not be there, remove it immediately, and, every time!  Each time you urinate, if you are sexually aroused, have sex, or masturbate and ejaculate, pre-ejaculate, obviously - all these must be removed from your penis on each occasion as soon as possible. 

Believe it or not, the clothes we wear can have hidden chemicals that become an extreme irritant to the penis, and in particular, the head and foreskin of the penis. So, if you can, ONLY wear plain white underpants / briefs / boxers - whatever you wear.  Then, you should wash these separately from other clothes.  If you are sportingly active, and have specific activity clothing, you can wash these along with your underclothes with pure soap flakes.  You can get these from any large supermarket in liquid form so that you can put them all together in the washing machine.  NEVER add pre-wash powders or treatments, or fabric conditioners!

In terms of your own hygiene, always protect the head and foreskin of the penis, EVERY time you have a shower: draw the foreskin as far forwards as it will go.  Never let hair shampoo, soaps, shower gels / lotions or anything like that get any where near the head of your penis.  Have a dedicated towel at home that you can ONLY use, for drying your penis.  When you are away from home, if you can still wash your penis, or, if not, use toilet tissue to 100% dry the skin of the penis and remove any trace of urine, etc.  If you use condoms, you may have an allergic reaction going on.  As I mentioned, lubes, even baby oil, etc, can, over time, become an extreme irritant to the head and foreskin of the penis.  Think about everything that comes into contact with the skin of your penis, could it be THE irritant?, do you have to use it?, should be your questions, every time!

If this situation persists for you, you may benefit from seeing a dermatologist.  Are you in the UK, or are in a country where you could potentially access such a specialist? It would be helpful if you can update your discussion forum on here, whatever happens, particularly if you find something that made a change for the better .....