Is a red spot post-PEP a sign of an STD in a man?

Question

Hello doctor,

It has been 34 days since a sexual encounter with someone who did not disclose they were a sex worker. I just finished PEP (post-exposure prophylaxis) Biktarvy (Bictegravir, Emtricitabine, Tenofovir alafenamide) on Tuesday and was tested at 17 days, negative for gonorrhea, chlamydia, and syphilis. The results for gonorrhea and chlamydia should be fairly definitive at that time, but syphilis may take longer.

Today I noticed a small red spot, about 1 cm (0.39 inches) across, on the bottom outer edge of my penis head. I think it is likely due to friction from my soap (which has small beads in it), clothing, or from masturbation without lubrication. Because of my recent exposure, I do not fully trust my assessment and would like another opinion.

Given its progression in healing, it is friction. I applied Aquaphor (Patrolatum) last night and twice today. I also have Neosporin (Neomycin, Polymyxin B, and Bacitracin) available.

Do you agree with my assessment, and what should I do for the next steps?

I am four days post-PEP at this time, with no rash or other symptoms present elsewhere. There have been no visible sores anywhere else on my body and no sign of a chancre. I did have a sore throat lasting about 24 hours a few days ago, likely from post-nasal drip, as I have chronic sinus issues and had not used Flonase (Fluticasone) that day.

Please help.

Thank you.

Answer 1

Hello,

Welcome to icliniq.com.

I have gone through your query and understand your concern.

Looking at the images and your description, the spot appears more like a superficial area of irritation rather than a classic infectious lesion. Friction or irritant dermatitis is very plausible, especially since you used a soap with beads, wear clothes, and mentioned masturbation without lubrication. These factors can easily cause small, red, flat patches like the one shown.

To help you feel more confident and clear about what you are dealing with, I will explain each of your STD (sexually transmitted disease)-related findings.

Syphilis chancre typically appears as a firm, round ulcer (often painless) that does not heal in a day or two. Your lesion looks more like a surface irritation and not a deep ulcer. Herpes lesions usually start as grouped vesicles (blisters) that then ulcerate; nothing in your photos resembles that pattern. No discharge, swelling, or widespread rash also makes a bacterial or systemic STI (sexually transmitted infections) less likely.

I would advise you as follows for your situation.

Keep the area clean and dry. Switch to a very mild, fragrance-free soap. Avoid soaps with beads or exfoliating agents.
Aquaphor (Patrolatum) is suitable for healing and barrier protection. If the spot looks irritated, you can use Neosporin (Neomycin, Polymyxin B, and Bacitracin) for two to three days, but avoid long-term use (risk of sensitization).
Use lubrication if masturbating, wear loose underwear, and let the skin rest. You should see steady improvement if this is irritation within a few days.

If it worsens, develops into an ulcer, blisters, or does not improve in a week or so, get re-examined.

I will also tell you about the testing timelines. Syphilis testing is usually repeated at six weeks, three months, and sometimes six months post-exposure. For HIV testing, if you have just finished PEP (post-exposure prophylaxis), the window period is shifted. A 4th-generation test is recommended six weeks after finishing PEP (around 10 weeks after exposure), with a confirmatory test three months post-PEP.

I hope I have answered your question.

Let me know if I can assist you further.

Thank you.

Answer 2

Hello,

Welcome back to icliniq.com.

Wait for one week, and watch for any worsening as described.

I hope I have answered your question.

Let me know if I can assist you further.

Thank you.

Answer 3

Hello,

Welcome back to icliniq.com.

You are thinking about this very logically, so I will tell you by timeline and presentation:

1. The incubation period for Gonorrhea/Chlamydia is usually 2 to 10 days. The symptoms are most often urethritis or discharge, not isolated skin lesions. A negative NAAT (nucleic acid amplification test) at 17 days is conclusive. Your assessment is correct: the red spot at day 33 is not consistent with gonorrhea or chlamydia.

2. The first episode of HSV (herpes simplex virus) usually appears 2 to 12 days after exposure. It begins with tingling or burning, then grouped vesicles, followed by painful erosions or ulcers. Appearance more than 30 days after a single exposure, without any prior lesions, would be very unusual. You are correct that HSV first appearing at day 33 is highly unlikely.

3. In syphilis, a primary chancre typically appears 10 to 90 days after exposure, on average, around 21 days. It presents as a single, firm, painless ulcer, not just a superficial red spot. It could still theoretically appear at 33 days, but what you have shown does not look like a chancre (no ulceration, induration, or rolled edges). This is the only STI (sexually transmitted infection) where timing could fit, but the morphology does not match.

4. For HIV (human immunodeficiency virus), the acute retroviral symptoms, including fever, rash, sore throat, and lymphadenopathy, usually occur two to four weeks after exposure. You are on PEP (post-exposure prophylaxis), which further reduces and delays risk. Skin lesions like this are not a presentation of acute HIV. This lesion is unrelated to HIV.

At day 33, a new superficial red patch like yours is incongruent with gonorrhea, chlamydia, HSV, or HIV. The only STI still in the timing window would be syphilis, but your lesion does not resemble a chancre. It looks much more consistent with friction or irritation.

I hope I have answered your question.

Let me know if I can assist you further.

Thank you.