What causes vaginal irritation after exposure to semen and how is it treated?

From the Guidelines

Vaginal irritation after exposure to semen is typically caused by a semen allergy (seminal plasma hypersensitivity), which occurs when a woman's immune system reacts to proteins in her partner's semen. Symptoms usually appear within minutes of exposure and include redness, swelling, burning, itching, and discomfort in the vaginal area. Treatment options include using condoms to prevent direct contact with semen, taking antihistamines like Benadryl (diphenhydramine) 25-50mg or Zyrtec (cetirizine) 10mg before sexual intercourse to reduce allergic reactions, and applying cool compresses or taking a cool bath to relieve symptoms. For immediate relief of existing irritation, over-the-counter hydrocortisone cream (0.5-1%) can be applied to external genital areas, but not internally. In severe cases or for long-term management, desensitization therapy performed by an allergist may be necessary, which involves gradually exposing the woman to increasing amounts of her partner's semen under medical supervision 1.

Some key points to consider in the diagnosis and management of seminal plasma hypersensitivity include:

• The condition is essentially a diagnosis by exclusion, and a detailed history is essential to rule out underlying causes such as sexually transmitted diseases, latex sensitivity, or transfer of food or drug proteins from the male sexual partner to the female who might be sensitized to these agents or other contactants 1.
• The diagnosis is confirmed by means of skin and/or in vitro tests for serum-specific IgE by using proper reagents obtained from fractionation of seminal fluid components 1.
• Prevention of reactions to seminal fluid can be accomplished by barrier use of condoms 1.
• Immunotherapy to properly fractionated seminal fluid proteins has been universally successful in preventing anaphylaxis to seminal fluid, provided the sensitizing seminal fluid fractions are used as immunogens 1.

It is also important to note that seminal plasma hypersensitivity is not associated with infertility, and successful pregnancies have been achieved after artificial insemination with sperm washed free of seminal plasma 1. If symptoms are severe or include difficulty breathing, seek immediate medical attention as this could indicate anaphylaxis, a serious allergic reaction.

From the Research

Causes of Vaginal Irritation after Exposure to Semen

• Vaginal irritation after exposure to semen can be caused by an allergic reaction to specific protein components in seminal fluid, known as seminal plasma hypersensitivity 2, 3, 4, 5.
• The major allergen involved in this disorder is believed to be prostate-specific antigen, but other proteins are likely involved 2, 3, 4.
• Women with systemic reactions are frequently atopic, and symptoms can manifest after first-time intercourse in up to 50% of cases 2, 3, 5.

Symptoms of Seminal Plasma Hypersensitivity

• Symptoms can be localized, including vaginal irritation, itching, and swelling, or systemic, including urticaria, angioedema, wheezing, dyspnea, gastrointestinal symptoms, or frank anaphylaxis 4, 5.
• Localized reactions are likely mediated by a non-IgE immunologic mechanism, while systemic reactions are likely elicited by an IgE-mediated reaction to seminal plasma proteins other than spermatozoa 5.

Diagnosis of Seminal Plasma Hypersensitivity

• Diagnosis is based on clinical history, and the gold standard for diagnosing seminal plasma hypersensitivity is prevention of symptoms with the use of a condom 2, 3, 4, 5.
• Skin prick tests and/or serum-specific immunoglobulin E to whole seminal fluid or fractionated seminal plasma proteins can also be used to diagnose the condition 2, 3, 4, 5.

Treatment of Seminal Plasma Hypersensitivity

• Treatment involves either avoidance with the use of condoms, intravaginal graded challenge using dilutions of whole seminal fluid, or subcutaneous desensitization to relevant fractionated seminal plasma proteins obtained from the woman's sexual partner 2, 3, 5.
• In patients with a desire for children, washed, SP-free spermatozoa can be used for insemination, and desensitization may be considered 4, 5.
• Data indicate that women with localized reactions have variable fertility outcomes, although the majority are able to have resolution of symptoms after desensitization and have normal term pregnancies 5.