(ABC NEWS) -- Newlyweds Jeff and Clara, both 35-year-old professionals, fell in love quickly and were convinced they were the "right match" -- until they had sex.
"I had this bizarre reaction," said Clara, who for privacy reasons did not want to use her real name. "I had burning and swelling and redness, which was very unusual. I thought I had contracted an STD [sexually transmitted disease]."
Horrified, she made an appointment with the gynecologist for testing and was nervous about having a "tricky conversation" with Jeff.
After several doctors' visits and hours of research online, the North Carolina couple finally got some answers, but it derailed their sex life and shook their marriage.
Clara had seminal plasma hypersensitivity, an allergic reaction to the proteins in Jeff's semen. Even using a condom didn't help, so the couple avoided intimacy.
"It's really bizarre," said Jeff. "Neither of us had ever come across anything like that. It was a real problem, because everything else was great. We were madly in love, but it was a real game-changer for a while."
Her condition affects an estimated 20,000 to 40,000 women in the United States, according to Dr. Jonathan Bernstein, a professor at the University of Cincinnati, who specializes in allergies and immunology and recently treated the couple.
"We feel they are more common," he said. "Not common like asthma, but more than people realize."
Some women have been known to sleep with their new husband for the first time and break out in hives. Women can experience abdominal swelling or a local reaction that they describe as "like a needle sticking in to their vagina," according to Bernstein.
Fertility is never affected. Once the woman is desensitized and can have sex comfortably, the chances of getting pregnant are the same as any other couple.
But women often don't get an accurate diagnosis because the condition can be confused with yeast and vaginal infections.
Dr. Andrew Goldstein, director of the Centers for Vulvovaginal Disorders in Washington, D.C. and New York City, said the condition is so uncommon, he has only treated "about a dozen" cases in the last 10 years.
"What is more common are hypersensitivities to latex or spermicides or even a chemical on your partner," he said. Lubricants and warm gels can also be allergens, he said.
Goldstein, who did not treat the couple, said men do not typically experience allergies to their wives. But a lingering mystery that still baffles the couple: Jeff has had similar allergic reactions to Clara -- but only when she has pain. Taking antihistamines on the advice of his allergist helped.
"His reaction is not typical and he only had it once or twice," said his doctor, Bernstein "I'm not sure what to make of it."
Oddly, Clara was also developing yeast infections after sex. She said this and the allergic reaction had never happened before in previous relationships.
"The swelling was worst immediately after sex," Clara said. "It would take 24 hours to subside and my skin would be irritated as if you'd put a chemical on it that caused it to burn. It was almost raw and took a while to heal."
The "gold standard" for treating semen allergies is to isolate the proteins in the man and do skin testing on the woman to determine which are to blame. Then, the woman is desensitized to the allergen.
The couple said they knew Bernstein was the top expert in the field, but the cost was daunting, so they put off making an appointment. But that took a toll as the couple started to avoid sex.
"In a normal romantic relationship, you want to feel attractive to your partner and want to do things that make you feel sexy," Clara said. "I feel like we actually started to define ourselves -- minimizing things to avoid sex. Funny, I started thinking I wouldn't wear sexy underwear. ... What seemed like medical problems had bigger effects."
"It pretty much dramatically reduced our libido," Jeff said. "We really haven't had much sex at all for the last 10 months."
They didn't share their concerns with anyone.
"When your mom calls up and asks how's married life? ... It's something we've been facing privately," Clara said.
Jeff said they started feeling "isolated, like total weirdoes," wondering why this would happen to them. "The intimacy level drops dramatically -- all of a sudden instead of living with your new wife or husband, you are more like roommates."
Finally, Jeff said, they "couldn't take it anymore," so they called Bernstein to learn he would take their insurance. They were told to set aside two days for allergy testing.
Just two weeks ago, Clara underwent an intravaginal "graded challenge" using serial dilutions of her husband's seminal fluid, which were injected via a syringe every 15-20 minutes over the course of two to three hours.
Their homework was to have sex within 12 hours and "see how it went," Clara said. Her symptoms "resolved substantially," according to Bernstein, who had her rate the pain.
"It was pretty much fine," she said. "There was a small amount of swelling, but compared to previous times, it was much less."
Bernstein told them to have sex again in a couple of day and to continue every few days. Each time went well. "Now," Clara said, "I am interested in having sex again."
Some of the couple's blood tests have still not come back, but the couple is guardedly optimistic. Clara and Jeff say they wanted to share their story to help others.
"It was kind of bizarre to be told, go have sex, especially after pretty much going cold turkey," Jeff said. "I think psychologically, we are back to a sense of normalcy."
Just the other morning, Clara made a move she hadn't done in months -- she initiated sex with Jeff.
"He said, 'It can probably wait until tomorrow. I don't want you to feel pressured,'" Clara said. "I wasn't even thinking that,' I told him. 'I just wanted you.'"
"This has been a very hopeful experience for us," Jeff said. "On a number of levels, it's been restorative. A whole side of our relationship really suffered. Now it's a whole new world."
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