Allergic to semen?

Dear Alice!

I am not actually worried but simply curious. When petting with my boyfriend and getting in contact with his sperm, my skin turns slightly red where his cum touches me. Am I allergic, or is there perhaps any other explanation? I am 24 years old and female.

Thank you in advance.

— Sex Flush

Dear Sex Flush, 

Sounds like this petting may be getting you all hot and bothered and not necessarily in a pleasant way! While an allergy to the proteins in your boyfriend’s sperm—known as seminal plasma protein hypersensitivity—may be a reason for this reaction, there are other reasons that may also provide an explanation. Given that there are multiple potential explanations, meeting with a health care provider may be helpful, as they can perform diagnostic tests to help you identify the cause of your irritation. 

It’s possible to have an allergic reaction to the proteins found in semen or to have allergies to a specific person’s proteins! A semen allergy can be categorized as either localized or systemic. A localized semen allergy affects only the body parts that come into direct contact with the semen. Symptoms typically occur within minutes of contact and can include burning, itching, or pain in the contact area. On the other hand, a systemic semen allergy can affect your entire body, causing life-threatening symptoms such as difficulty breathing, anaphylactic shock, hives, swelling, chest tightness, and vomiting within minutes of contact. Individuals at risk for this condition typically have a history of allergic disorders, prior reproductive surgical procedures, or are currently pregnant or experiencing menopause. Additionally, those assigned female at birth are more susceptible to developing this condition for unknown reasons. 

People with more severe symptoms may want to keep an emergency kit on hand. Some of the items in there may include antihistamines, oral cortisone, or epinephrine injections for more severe allergies. Other treatment options can include desensitization, which is the act of consistently coming into contact with semen until symptoms are reduced, or the use of condoms to prevent exposure to the semen altogether. 

That being said, a semen allergy is just one of many possible explanations for your symptoms. Other explanations can include: 

  • Vaginal conditions. If you’re experiencing these symptoms in or around the vaginal area, it may be related to a sexually transmitted infection (STI), such as chlamydia, gonorrhea, or genital herpes. Additionally, conditions such as bacterial vaginosis, yeast infections, and eczema can also cause itching and burning in the genital area. 
  • Other allergies. There are some rare instances of allergens being passed through sexual fluids. Certain medications, like chemotherapy drugs, can also remain in the body for several days and be flushed out of the body through sexual fluids. Are you allergic to any medications or foods that your partner may have consumed prior to getting it on? Did you use any lubricants, contraceptives, or spermicides? If so, you may want to consider performing a patch test to see if these products may be causing your symptoms. 
  • Chronic hives. Hives—or urticaria—are a type of immune response caused by the release of histamine. Triggers can include vigorous activity, temperature changes, sunlight, pressure, vibration, and medical conditions like cancer or infection. 

If you believe that you may have any of these conditions or you develop more serious reactions, consider speaking with a health care provider for further diagnosis and treatment, if necessary. Until then, using a condom, if you’re not allergic, may be helpful in reducing contact with your partner’s semen and preventing further reactions from occurring. 

Hopefully any future petting happens without the rashes! 

Last updated Dec 29, 2023
Originally published Apr 18, 1994