ITCHY genitals, a burning sensation, and feeling breathless are all considered normal after sex.
But for a growing number of women, these symptoms could be a sign of seminal plasma hypersensitivity (SPH) – an allergy to semen.

A growing number of women could suffer with a semen allergy[/caption]
While it’s considered a rare allergy, it’s also underdiagnosed.
And Michael Carroll, associate professor in reproductive science at Manchester Metropolitan University, explains it isn’t triggered by sperm cells, but the fluid that carried the sperm.
He said: “First documented in 1967, when a woman was hospitalised after a ‘violent allergic reaction’ to sex, SPH is now recognised as a type 1 hypersensitivity, the same category as hay fever, peanut allergy and cat dander.”
Writing for The Conversation, Carroll says symptoms of SPH can range from mild to severe.
While some women experience local reactions, such as burning, itching, redness and swelling of the vulva or vagina, others develop full-body symptoms, like hives, wheezing, and even anaphylaxis.
He added: “Until 1977, SPH was thought to affect fewer than 100 women globally.
“But a study led by allergist Jonathan Bernstein found among women reporting postcoital symptoms, nearly 12 per cent could be classified as having probable SPH.
“I conducted a small, unpublished survey in 2013 and found a similar 12 per cent rate. The true figure may be higher still.
“Many cases go unreported, misdiagnosed, or dismissed as STIs, yeast infections, or general ‘sensitivity’.
“One revealing clue: symptoms disappear when condoms are used.”
The main allergen, according to Carroll, is prostate-specific antigen – a protein produced by cells in the prostate gland.
And cross-reactivity is a possibility, for example, f5, a protein found in dog dander, is structurally similar to PSA.
So a woman allergic to dogs may also be allergic to semen too.
Also, woman may not be the only ones affected, said Carroll.
It’s possible some men be allergic to their own semen too.
A paper published in American Journal of Case Reports described a 22-year-old was consumed by sneezing, watery eyes, stomach cramps, muscle pain and deep fatigue in the hours after climaxing.
The condition is known as post-orgasmic illness syndrome (POIS).
While SPH doesn’t cause infertility directly, it can complicate conception.
Carroll said: “Avoiding the allergen – usually the most effective treatment for allergies – isn’t feasible for couples trying to conceive.
Treatments include prophylactic antihistamines (antihistamine medications taken in advance of anticipated exposure to an allergen, or before allergy symptoms are expected to appear to prevent or reduce the severity of allergic reactions), anti-inflammatories and desensitisation using diluted seminal plasma. In more severe cases, couples may choose IVF with washed sperm, bypassing the allergic trigger altogether.
When to call 999 after an allergic reaction
Call 999 if:
- your lips, mouth, throat or tongue suddenly become swollen
- you’re breathing very fast or struggling to breathe (you may become very wheezy or feel like you’re choking or gasping for air)
- your throat feels tight or you’re struggling to swallow
- your skin, tongue or lips turn blue, grey or pale (if you have black or brown skin, this may be easier to see on the palms of your hands or soles of your feet)
- you suddenly become very confused, drowsy or dizzy
- someone faints and cannot be woken up
- a child is limp, floppy or not responding like they normally do (their head may fall to the side, backwards or forwards, or they may find it difficult to lift their head or focus on your face)
You or the person who’s unwell may also have a rash that’s swollen, raised or itchy.
These can be signs of a serious allergic reaction and may need immediate treatment in hospital.
Source: NHS