Penetrating Questions | Yes, it is possible to be allergic to semen

Jina Ashline Columnist

My partner got a little semen on my arm when he ejaculated the other day and I became itchy in that spot. Another time, I swallowed during oral sex and my throat became irritated and felt tight. Could I be allergic to his semen?
- Itching to Know

Dear Itching,

You could indeed potentially be allergic to his semen! Some people have allergic reactions to proteins in their partner’s semen, a condition sometimes called “human seminal plasma hypersensitivity.” The allergy may be a reaction to a protein found in most men’s semen or only in the semen of a certain partner. The first documented case of a semen allergy was reported in 1958.

Both women and men can have this reaction, which occurs when their bodies produce “sperm antibodies.” The antibodies cause an immune response that is often similar to a mild case of hay fever. People with allergies to other things tend to be more prone to semen allergies. In addition, more people may have the allergy than are aware of it because they may associate irritations with other problems, such as a sexually transmitted infection (STI) or a condom allergy.

There are varying explanations for why a person might have an allergy to a partner’s semen. But for men who are allergic to their own semen, the reason is clearer. A man will often develop antibodies to his own semen if it comes into contact with his blood, after a vasectomy, with testicular torsion (where a testicle twists inside the scrotum), with an infection, or after trauma to the testicles.

Symptoms of a semen allergy typically are mild and include redness, burning and swelling where the semen has contacted the skin. Most symptoms typically start within 20-30 minutes of contact and can last for hours or even days. A small number of people may have more severe reactions including hives, itching, swelling and difficulty breathing.

While there have been no reported deaths from an allergic response to semen, some people have required hospitalization after experiencing these more severe symptoms. The severity of the reaction depends on your own personal body chemistry. You should see a doctor if you ever experience an extreme allergic reaction.

If you are experiencing redness or itching after sex around the genitals, other potential explanations for your reaction could be a yeast infection, bacterial vaginosis, or an STI, such as chlamydia. It is important to get tested for STIs to rule out infection as the cause of your irritation.
The allergy does not significantly affect most people’s sex lives, but it tends to be most problematic for couples that are trying to conceive because the antibody will make fertilization more difficult. Very few fertile couples have semen allergies (less than two percent), while seminal allergies plague 5-25 percent of those with fertility problems.

If you do indeed have this allergy, the best way to treat it is to reduce or eliminate contact with your partner’s semen. Using condoms with every sex act is usually sufficient to prevent further reactions. The extra advantage is that condom use will also help prevent STIs and pregnancy! There are other treatment options available, like desensitization to the semen, which a doctor can help with.
Since we’re on the subject of semen and sperm, I thought I’d share some interesting tidbits and confront some myths about those little swimmers that helped form us.

Human sperm is about 1/5000 of an inch long and is one of the smallest cells in the human body.
A fertile male human ejaculates between two and five millileters of semen with each ejaculation. This is about one teaspoon full on average. One ejaculation contains about 100 million sperm-per-millileter, and yet the quantity of sperm produced will only cover the head of a pin.

Even though it only takes one sperm to fertilize an egg, if the concentration of sperm falls below 20 million sperm-per-millileter, there is usually trouble with fertility because only a small fraction of the sperm deposited in a woman’s vagina make it to her uterus, and even less make it to the oviducts where fertilization takes place. They have a long way to travel and only a small amount will make it, so there must be a lot of contenders!

Interestingly, allergens besides semen allergens can be transmitted through semen. These can include medications such as penicillin, and even some foods and beverages, such as walnuts.
There is no need to have sex or masturbate to ejaculate for health reasons. The body is able to deal with unused sperm with no impact on a man’s future fertility or sex drive.

Semen does not have a significant amount of calories. Dr. Franklin Lowe, associate director of Urology at St. Luke’s/Roosevelt Hospital Center in New York, estimated that a person would have to ingest 400 loads of ejaculation to equal the calorie content of a “death by chocolate” dessert.

What a man eats can impact what his semen will taste like. While there are no studies to support the different kinds of taste, it is generally believed that kiwi, celery, pineapple and watermelon can all make semen taste pleasant. Heavy beer and coffee drinkers are said to produce bitter-tasting semen, while alkaline-fish and meats create a buttery taste.

A report in 2003 that was widely publicized claimed that swallowing semen would reduce a woman’s risk of developing breast cancer, but there is no truth to that claim.

Similarly, swallowing semen will not help whiten teeth, as some believe.

If a woman swallows the semen of the man with whom she is hoping to become pregnant, it can aid her chance of successful fertility because it helps a woman’s immune system get used to her partner’s sperm.

Semen absorption through sex has been shown to have a mood-elevating effect on women.

—Jiná Ashline ’08 is a religion major with a women’s studies correlate. She is also president of C.H.O.I.C.E. Each week she will answer a question about sex and sexuality. Send your questions to jiashline@vassar.edu or by dropping a note in Box 2172.