A mysterious postcoital illness afflicting men has scientists puzzled as to why some men appear to be allergic to their own semen.
A new study published this month in Sexual Medicine Reviews details what researchers at Tulane University in New Orleans know about post-orgasmic illness syndrome (POIS).
Spoiler: It's not much.
First documented in medical journals in 2002, POIS manifests as flulike symptoms within seconds, minutes or hours after ejaculation.
Victims may experience confusion, inability to speak, read or write, muscle pain, fatigue, itchy eyes, feverishness and influenza symptoms, The Independent reports.
This mysterious illness "negatively affects the life of patients by limiting sexual encounters, dampening romantic prospects, creating internal struggles to avoid eroticism and affecting patients’ schedules," according to the study's abstract.
About 50 cases have been documented over the past 15 years, yet scientists still don't know the root of this debilitating condition.
"Further studies are warranted to investigate the prevalence, pathophysiology and treatment" of POIS, the study's authors wrote.
In another study on the condition from 2011, researchers tried standard skin-prick allergy tests with the participants' own semen. Eighty-eight percent of them showed signs of auto-immune allergic reactions. In that study, Dutch researcher Marcel Waldinger said a standard allergy treatment called hyposensitization therapy could help reduce the condition's severity.
“It’s a very slow process. It is used for all sorts of allergies and can sometimes take up to 5 years,” Waldinger told Reuters in 2011.