Men who get a flu-like illness after sex may be allergic to their own semen, say Dutch scientists. The condition, known as post orgasmic illness syndrome (POIS), causes fever, runny nose, extreme fatigue and a burning sensation. in the eyes. Symptoms appear minutes after orgasm and can last up to a week. The mysterious syndrome has been documented in medical journals since 2002, but little is known about it, what causes it, and how it can be treated. In this direction, Prof. Marcel Waldinger from the University of Utrecht published two studies in the “Journal of Sexual Medicine” that try to provide answers to these questions. According to the first study, the syndrome is most likely caused by an allergic reaction to sperm, and the second study suggests a therapy that could help alleviate the male problem. “The results are an important breakthrough in the study of this syndrome. They contradict the idea that complaints are due to psychological reasons,” says Prof. Waldinger. His team analyzed 45 Dutch men who were diagnosed with the disease. 33 of them agreed to undergo standard skin allergy tests as well as an examination of their semen. Eighty-eight percent of the men had a positive skin reaction, indicating an autoimmune response or allergic reaction, the researchers said. The procedure involves injecting and gradually increasing doses of the volunteers’ own sperm. Both saw a reduction in symptoms and improvement after 1 to 3 years, explains Prof. Waldinger.