Sex can make men sick, scientists have found.
Men are at risk of suffering post orgasmic illness syndrome (POIS), which causes feverishness, runny nose, extreme fatigue and burning eyes.
The sex symptoms appear minutes after climax and last for up to a week.
Although the mysterious sex syndrome has been documented in medical journals since 2002, little was known about what caused it and how it could be treated.
The Journal of Sexual medicine now contains two studies that shed more light on the affliction.
Professor Marcel Waldinger from Utrecht University has found that the syndrome is probably caused by an allergic reaction to semen.
He also suggests that hyposensitisation therapy could help affected men.
Men who are crippled with the syndrome after sex can rest assured that there is nothing wrong with their heads.
Professor Waldinger said his findings “contradict the idea that the complaints have a psychological cause.”
It comes as a relief to sufferers, who experts say often feel confused and ashamed about the sex condition.
The findings come after Professor Waldinger and his team analysed 45 Dutch men who were diagnosed with the illness.
“They didn’t feel ill when they masturbated without ejaculating, but as soon as the semen came from the testes… after that they became ill, sometimes within just a few minutes,” he said.
Thirty-three of them agreed to undergo a standard skin-prick allergy test using a diluted form of their own semen.
Of those, 29, or 88 per cent, had a positive skin reaction indicating an auto-immune response, or allergic reaction.
In a second study the team treated two of the volunteers with hyposensitisation therapy – a well-known technique for treating allergies.
It repeatedly exposes the body to small but gradually increasing amounts of the allergen over several years.
They found that the men showed a significantly reduction in their POIS symptoms after one and three years.
Professor Waldinger’s team has now started several more POIS patients on hyposensitisation therapy.
More people in the world enjoying sex – that can’t be a bad thing!