This is nuts!
For a small but suffering contingent of women, an allergy to semen is seriously interfering with intimacy.
A semen allergy, also known as seminal plasma hypersensitivity (SPH), is a rare reaction to proteins found in male spermatic fluid, according to the Cleveland Clinic.
SPH is recognized as a Type 1 hypersensitivity, characterized by a rapid, exaggerated immune response to an allergen, putting semen in the same category as peanuts and pet dander.
For those afflicted, reactions to exposure to ejaculate run the gamut from burning, itching, redness and swelling of the vulva or vagina to hives, shortness of breath, dizziness and even anaphylaxis.
One Colorado college student with SPH reported that oral sex led to inflammation and temporary facial paralysis. She said that the severity of the side effects depends on the quantity of sperm she’s encountered.
Experts believe the condition, which can be life-threatening if there’s anaphylaxis, is underreported.
SPH was first documented in 1967, when a woman was hospitalized following a “violent allergic reaction” to sex.
For the next three decades, it was assumed that SPH affected fewer than 100 women worldwide.
Yet, a 1997 study led by allergist Jonathan Bernstein revealed that nearly 12% of reported postcoital symptoms could be classified as SPH.
In 2013, Michael Carroll, an associate professor in reproductive science, conducted a small, unpublished survey that found a similar rate.
However, he maintains that the true number may be much higher.
“Many cases go unreported, misdiagnosed or dismissed as STIs, yeast infections or general ‘sensitivity,’ ” Carroll wrote this week in The Conversation.
“A 2024 study reinforced this finding, suggesting that SPH is both more common and more commonly misdiagnosed than previously believed.”
This condition is now believed to affect one in 40,000 people.
Experts maintain that the main allergen is not sperm cells themselves, but prostate-specific antigen (PSA) in seminal plasma.
Interestingly, there appears to be cross-reactivity.
Carroll notes that Can f 5, a protein found in dog dander, is structurally similar to human PSA, meaning that women allergic to dogs may have a higher likelihood of experiencing an allergic reaction to semen.
It is also possible to be exposed to an allergen through ejaculate.
In 2022, OnlyFans star Lucy Banks shared her experience of suffering an allergic reaction to peanuts from her partner’s ejaculate.
She has since been spreading a warning to others about the dangers of sexually transmitted food allergies — especially from a peanut-loaded penis.
Diagnosis of SPH is, of course, made via skin prick.
While condoms mitigate the risk of allergen exposure to PSA, for some unlucky lovers, allergies to semen and condoms make intimacy particularly troublesome.
SPH does not directly cause infertility, though conception can be challenging. Treatments for would-be parents include antihistamine medication before intercourse, anti-inflammatories after and/or desensitization therapy using diluted seminal plasma.
In cases where the allergic reaction is severe, some couples turn to IVF using washed sperm free from seminal plasma to divert the allergic trigger.
In rare instances, men can be allergic to semen.
Known as post-orgasmic illness syndrome (POIS), the condition is characterized by extreme fatigue, weakness, a fever or sweating, mood changes or irritability, problems concentrating, a stuffy nose and itching eyes following intercourse.
These symptoms can occur within seconds, minutes or even a few hours after ejaculation — and they can last from two to seven days.
POIS was first documented in 2002, and more than 50 cases have been recorded worldwide. However, experts believe that, similar to SPH, the actual incidence rate could be even higher.
Believed to be an autoimmune response or allergic reaction, POIS is also diagnosed via skin testing.
