Non-Itchy Red Rashes: Allergies or Something More?

Widespread rash all over the body, non-painful and non-itchy?

On February 25th, I engaged in unprotected sexual activity with a partner using only my hands and mouth, but it lasted only a brief moment and there was no ejaculation.
After returning home, I noticed red spots near my abdomen that resembled mosquito bites but were not itchy.
I applied Mentholatum for two days, and they almost disappeared.
On March 1st, after work, I discovered some red rashes on my hands that were not painful.
The next day, I woke up to find the rashes spread across my limbs, including my palms and soles.
I did not go to the hospital, but a doctor said there was no need for blood tests and that it might be an allergy, although I have never experienced allergies before.
My skin has always been good, but I recently increased my intake of dietary supplements.
I usually take Centrum, marigold lutein, and iron effervescent tablets, spaced about two hours apart.
Recently, I also bought maca, zinc (taking them simultaneously), collagen powder, and vitamin C.
I would like to know if taking too many dietary supplements could have caused the rashes or if it could be a sexually transmitted infection.
An internal medicine doctor referred me to a dermatologist, where I received an injection and took antihistamines for two days.
I feel that the rashes have significantly improved, so is it really just an allergy? Should I not worry too much?

Niming, 20~29 year old female. Ask Date: 2024/03/03

Dr. Wu Yuxin reply Dermatology

All the doctors you have seen have said that you have allergies.
Are you still not at ease? If you are concerned about sexually transmitted infections, you can consult an infectious disease specialist or a dermatologist for an examination, and you may need to have blood tests for confirmation.

Reply Date: 2024/03/03

More Info

When it comes to the appearance of non-itchy red rashes, especially after a recent sexual encounter, there are several factors to consider. Based on your description, it seems that you experienced a sudden onset of red rashes on your abdomen and later on your limbs, which were not itchy. This can be concerning, but it is important to analyze the situation carefully.

Firstly, the timing of your symptoms following a sexual encounter raises the question of whether this could be related to a sexually transmitted infection (STI). However, many STIs typically present with additional symptoms such as itching, burning, or discharge. The absence of these symptoms, along with the fact that the rashes are not itchy, suggests that it may not be an STI. Nevertheless, it is crucial to consult a healthcare provider for proper evaluation and testing, especially if you have concerns about potential exposure.

Another possibility is that the red rashes could be an allergic reaction. You mentioned that you have recently started taking several new dietary supplements, including maca, zinc, collagen powder, and vitamin C. It is possible that one or more of these supplements could be causing an allergic reaction, especially if they contain ingredients that your body is not accustomed to. Allergic reactions can manifest in various ways, including rashes, and can occur even if you have never had allergies before. The fact that your doctor suggested it might be an allergy and prescribed antihistamines indicates that this is a plausible explanation.

Additionally, the rashes could be a result of contact dermatitis, which occurs when the skin comes into contact with an irritant or allergen. If you have changed any soaps, lotions, or other products that come into contact with your skin, this could also be a contributing factor.

Given that you have noticed improvement after taking antihistamines, it is likely that the rashes are indeed related to an allergic reaction. However, it is essential to monitor your symptoms closely. If the rashes persist, worsen, or if you develop new symptoms such as fever, swelling, or difficulty breathing, you should seek medical attention immediately.

In summary, while your symptoms may be indicative of an allergic reaction, it is important to remain vigilant and consult with a healthcare professional for a thorough evaluation. They may recommend allergy testing or further investigations to rule out other potential causes. It is always better to err on the side of caution, especially when it comes to new or unexplained symptoms.

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