From time to time, maybe once a month, the skin directly below my penis head will be dry and peel away in a circle around my penis.  It is under the edge of the head of penis.  I have been tested for all STDs, but this makes me very nervous.   When it peels away, there is not pain and the skin does not look irritated.  Does this sound like STI?   If not, what might it be?

I will start by observing that you clearly are overly concerned about STDs despite absence of significant risk and lack of any symptoms that suggest STDs; and the results of the tests negative for HIV, syphilis, etc. And there is no STD likely to cause peeling skin of the penis.

Do not assume that genital skin problems must be STDs. Not true. I have a book titled Genital Dermatology Atlas. As the title suggests, it is filled with photos and brief discussion of various genital skin rashes, lesions, bumps, etc. It's 300 pages long. In all those 300 pages, all STDs are covered in 15 pages. In other word, the vast majority of genital skin problems (over 90%) are not due to STD, and have nothing to do with sexual health.

We are STD experts, and do not deal with all genital medicine. There are several conditions that might cause skin peeling -- allergy, eczema, physical or chemical irritation, and others. Few if any are serious or dangerous. If the problem continues or you otherwise remain concerned, show the area to your doctor -- or ideally a dermatologist.

Please don't worry about STDs. For sure that's not the explanation.

I hope these comments are helpful. Let me know if anything isn't clear.

HHH, MD