What could be the cause of redness on the head of the penis?

Hi doctor,

I noticed redness on the penis head. It is not how it normally looks, but I have noticed this happening a few times over the last few months. In both cases, when I noticed it, I have been on or recently on Isotretinoin low dosage treatment, and I do not know if this has any relevance. Of other issues, I suffer from what doctors believe are muscle issues in my pelvic floor, which leads to soreness in the perineum after sex. This is another issue and not correlated directly to this issue though.

I do not feel any itching or pain associated with this. I believe the other times I had this, it went away after some days, but I do not know what is causing it. I only noticed it because my foreskin and urethra were slightly red than usual when I went to pee.

Please see the photos to easily see what I mean. Hopefully, someone can explain to me what this is. The last time I had it and went to my dermatologist, it had subsided before, and she saw nothing wrong with it, but now it is back. I masturbated a few hours prior and do not know if this is relevant. Also, I have been tested for everything recently regarding STDs, and I am clean and have had no sex in that time.

Thank you.

Hi doctor,

Thank you for the reply.

Could you please elaborate on the following questions since it was the same the last time I had this? Why is it mostly on the left side of the penis and not the right? (As can be seen in the photo).

1) Is Isotretinoin affecting this since I seem to be getting it either a week into treatment or shortly after ending it?

2)Applying the anti-fungal cream I had last time makes it feel warm on the penis. Is this a sign that it's infected?

3) I also feel some burning sensation on the scrotum. Is it likely this is connected? The Burning feels on the skin, and there may be some redness, but I have put Cotizon cream on the last few days that I got from my derm for similar complaints last time, which also resulted in red skin and burning.?

4) They found no fungi last time, but I felt the anti-fungal cream was effective. Could this be related to my using anti-fungal days before they did a swap test from the scrotum? I asked them this but was not getting an answer.

Thank you.