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10 extremely unusual allergies

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Sex

Talk about killing the mood! Known as human seminal plasma hypersensitivity, this condition involves a negative physical reaction to a man's seminal fluid (the liquid that carries sperm). Symptoms include hives, swelling and trouble breathing. The good news? Treatment is available, and can include simply using condoms or exposure therapy (a.k.a. spending plenty of time between the sheets to get desensitized to the reaction).