What Is Postorgasmic Illness Syndrome?
The underlying cause of POIS is not known. Some scientists believe that in men, it is an autoimmune or allergic disorder that causes an inflammatory reaction to a substance in a man’s own semen. Others have proposed POIS may be caused by a chemical imbalance in the brain. There is no standard treatment for POIS, but some men have been treated with SSRIs, antihistamines, and/or benzodiazepines. POIS can cause severe distress in people with the condition and their partners. Some people with POIS abstain from sexual activity or find that they need to schedule sex for a time when they can cope with the symptoms.
Source: Genetic and Rare Diseases (GARD) Information Center