Semen allergy is an allergic reaction to the proteins in semen. People may notice various symptoms after coming into contact with semen.

People may also refer to a semen allergy as a sperm allergy, semen contact allergy, or human seminal plasma hypersensitivity (HSP).

It is unclear how many people HSP affects. However, research suggests around 8% of females in the United States.

In this article, we examine semen allergy and who it affects. We also look and the causes and symptoms and the potential treatment options.

A note about sex and gender

Sex and gender exist on spectrums. This article will use the terms “male,” “female,” or both to refer to sex assigned at birth. Click here to learn more.

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People may experience symptoms 10–30 minutes following contact with semen, lasting for a few hours or up to a few days.

Symptoms usually resolve within 24 hours. However, localized pain, itching, and general malaise can continue for several days to weeks.

Once a person experiences symptoms of HSP, they will usually experience symptoms regardless of their sexual partner. However, in some cases, the symptoms may only develop with a specific sexual partner.

Localized reactions

Symptoms of a semen allergy may affect the vulvovaginal area, penis, or any area that comes into contact with semen, including the hands, mouth, chest, and anus.

Symptoms may be local to the affected area and include:

  • changes in skin color of the affected area
  • itching
  • pain
  • burning sensations
  • swelling

Blistering around the vulvovaginal opening and penis can also occur, although this is less common.

Systemic reactions

In some cases, HSP symptoms may affect the whole body, which can result in:

  • hives
  • difficulty breathing
  • swelling of the tongue, lips, and throat
  • gastrointestinal symptoms, such as nausea, diarrhea, and vomiting

If people develop symptoms of a severe, life threatening allergic reaction, or anaphylaxis, they should seek emergency medical attention.

Males can be allergic to their own semen. The term for this is post-orgasmic illness syndrome (POIS). POIS is a rare condition that causes a flu-like reaction after ejaculation.

People with POIS may have symptoms such as:

POIS may occur due to an autoimmune or allergic reaction to substances in semen or an imbalance of chemicals in the brain.

Semen allergy is a rare condition that occurs when the immune system reacts to the proteins in semen, causing an allergic reaction. No one knows why HSP develops.

Semen allergy most commonly affects females. Over 40% of women with HSP may experience it after the first time they have sexual intercourse.

Of those who develop HSP, over 60% of people may receive a diagnosis between the ages of 20–30. Some people may experience HSP for the first time following menopause.

People may experience HSP with one sexual partner and not another. It can occur suddenly with a long-term sexual partner.

People with a family history of HSP may be more at risk of developing the condition.

HSP can cause similar symptoms to other conditions, such as sexually transmitted infections (STIs), vaginitis, or yeast infections.

A doctor takes a medical history and assesses symptoms to diagnose HSP. They may carry out tests to help rule out other possible conditions, such as:

  • vaginal examination
  • vaginal swabs to check for any bacterial or yeast infections
  • nucleic acid amplification tests (NAATs), which help to rule out any STIs
  • blood tests

A doctor may perform a skin prick test using a sample of semen proteins from the person’s sexual partner. The doctor can then check for any reaction.

Treatment options for HSP may include:

  • using a barrier method such as a condom
  • taking an oral antihistamine 30–60 minutes before intercourse
  • having an epinephrine autoinjector, such as an EpiPen, to hand in case of a severe allergic reaction
  • desensitization treatment, which may include gradual dilutions of semen from a sexual partner into the vagina or injections of semen proteins under the skin

HSP does not directly affect fertility or pregnancy. However, it can affect the ability to conceive if people use barrier methods to protect themselves from an allergic reaction during intercourse.

If people with HSP wish to become pregnant, they may consider artificial insemination or in vitro fertilization (IVF). For these methods, washing the sperm prevents it from causing an allergic reaction.

In most cases, artificial insemination with washed sperm does not cause allergic reactions in people with HSP.

HSP may affect intimacy and may lead to sexual dysfunction and relationship issues.

In some cases, people may develop anaphylaxis, a severe allergic reaction. Anaphylaxis is life threatening, and people will require immediate medical attention.

Symptoms of anaphylaxis usually affect more than one area of the body and can include:

  • swelling
  • difficulty breathing
  • a red rash with itchy hives
  • wheezing
  • chest tightness
  • fainting
  • difficulty swallowing
  • hoarse voice
  • stomach cramps
  • vomiting
  • diarrhea
  • change of skin tone
  • a feeling of dread or impending doom

Anaphylaxis is a medical emergency. If people have a severe allergic reaction, they should use an epinephrine autoinjector and call 911.

HSP is rare. However, it can cause uncomfortable symptoms and affect a person’s sex life. Without treatment, a semen allergy may negatively affect a relationship.

Occasionally, HSP may cause a severe allergic reaction that requires immediate medical attention.

Although HSP does not directly affect fertility, it may make it more difficult to conceive through unprotected intercourse. People wanting to become pregnant may need alternative options, such as IVF.

In over 95% of affected females, desensitization injection treatment effectively relieves symptoms of HSP. The treatment must be ongoing for sustained results, with exposure to the semen two to three times a week.

HSP is an allergic reaction to the proteins in semen. People may have a semen allergy if they notice symptoms of an allergic reaction after coming into contact with semen.

Symptoms can be similar to other conditions, such as STIs, including itching, redness, and swelling. A doctor may perform a physical examination and a blood or skin prick test to diagnose HSP.

Treatment for HSP may include using barrier methods such as condoms, antihistamines, or desensitization to the allergen. People with HSP may need to use artificial insemination or IVF to conceive.

If people have a severe allergic reaction, they should seek emergency medical attention immediately.