In rare cases, people have been known to experience allergic reactions to seminal fluids, known as human seminal plasma hypersensitivity. Symptoms can be either localized or systemic, and may include itching, redness, swelling, or blisters within 30 minutes of contact. They may also include hives and even difficulty breathing. Treatment options for semen allergy include avoiding exposure to seminal fluid by use of condoms and attempting desensitization.
