Allergy to seminal fluid is known as seminal plasma hypersensitivity (SPH). SPH is rare, although it may be overlooked or misdiagnosed. SPH occurs when hypersensitivity to human prostate specific antigen (PSA) causes a systemic or localized allergic reaction following direct contact with seminal fluid during intercourse. Symptoms range from mild to severe, including pruritus, urticaria, wheezing, chest tightness, dizziness and anaphylaxis. Immunotherapy and desensitization treatments can be effective. Human prostate specific antigen shows cross-reactivity with the dog urine and dander allergen, canine prostatic kallikrein.

Worldwide distribution

Human seminal plasma hypersensitivity is rare, with most cases occurring in women in their twenties and thirties (2).

Risk factors 

Most patients with human seminal plasma hypersensitivity have atopic diseases such as allergic rhinoconjunctivitis or have a family history of atopy (2). An atopic background was reported in 84% of 49 patients (4).

Main

The main route of exposure is direct contact with seminal fluid.

Seminal plasma hypersensitivity (SPH) presents as an immediate local or systemic reaction following mucosal exposure to seminal fluid during sexual intercourse. Around half of patients develop symptoms after their first unprotected intercourse. Systemic SPH is a Type 1 hypersensitivity reaction characterized by pruritus, urticaria, angioedema, chest tightness, wheezing and dizziness, which may lead to hypotension and anaphylactic shock. Localized SPH causes vaginal pain and burning sensations, swelling and/or pruritus. Systemic SPH tends to have a rapid onset post coitus and lasts less than 24 hours, whereas the symptoms of localized SPH may take a few hours to develop and last up to several days (1).

In a review of 74 patients with SPH, 52 (70%) presented with systemic symptoms and of these, 29 also had associated local symptoms, while 21 patients (28%) had local reactions only and one patient presented with fixed cutaneous eruptions (4).

Symptoms of SPH may worsen over time, with progression from localized to systemic symptoms or progression in the severity of symptoms. Life-threatening anaphylactic reactions have been recorded in 16 out of 80 patients with SPH (4).

Other diseases

A rare form of seminal plasma hypersensitivity affecting men, known as post-orgasm illness syndrome (POIS), causes local and systemic symptoms within seconds to hours after ejaculation. These include flu-like manifestations, myalgia, fatigue, burning eyes, nasal congestion and, rarely, genital local reactions. POIS is hypothesized to be an auto-immune reaction to seminal peptides released from damaged urethral lining cells (1).

Allergen immunotherapy

Immunotherapy and desensitization protocols can be effective in systemic, IgE-related seminal plasma hypersensitivity. Local desensitization protocols have used intravaginal graded challenge (IVGC) with serial dilutions of whole seminal fluid (1, 4). Subcutaneous desensitization using whole seminal plasma is ineffective; however, rapid immunotherapy protocols using subcutaneous injections of specific fractionated seminal plasma proteins have been described as very effective (1, 5).

A hypo-sensitization protocol for POIS using subcutaneous injection of autologous semen has been reported as effective in a few cases (1). 

Prevention strategies 

Avoidance

The human seminal plasma allergen can be avoided by using condoms during intercourse (5). 

Other topics

Prophylactic usage of antihistamines and intravaginal cromolyn cream have been reported to prevent localized symptoms of SPH (4). A few cases of localized SPH have responded successfully to non-steroidal anti-inflammatory drugs (1).

Allergenic molecules

The major allergen of human seminal fluid is Hom s PSA (prostate-specific antigen), a member of the serine protease family of proteins (6).

Cross-reactivity

Patients allergic to the major dog allergen Can f 5 (canine prostatic kallikrein), found in male dog urine, dander and epithelium, may also show allergic reactions to human seminal fluid (1, 7). Women experiencing seminal plasma hypersensitivity after their first unprotected intercourse may have been sensitized by previous exposure to dog dander or urine (1).

In a small Spanish study, PSA-allergic patients were found to have higher Can f 5 specific IgE levels than PSA-sensitized, asymptomatic patients, while the latter group had higher sIgE levels than patients sensitized to Can f 5 and not to PSA. This suggests that the prevalence of seminal fluid allergy among women sensitized to kallikrein might be related to their levels of sIgE (7).

Author: RubyDuke Communications

Reviewer: Dr. Christian  Fischer 

Last reviewed: April 2022