BOSTON -- If there's a limit to the range of ways in which the human body can fail, medical science has yet to find it, and allergists may be more aware of that fact than clinicians in other specialties.
Poster presentations at the American College of Allergy, Asthma, and Immunology's annual meeting here highlighted the bizarre and every-expanding number of substances that the immune system can regard as noxious, ranging from Mom's breast milk to a man's own semen.
Some of these case reports were the first ever to describe such allergies, according to the physicians presenting them. That raises the question of their importance to the allergist community -- what is the value of knowing about a possible allergy that most clinicians will never encounter in their entire careers?
John Oppenheimer, MD, who headed the ACAAI's abstract selection committee for the meeting, had a ready answer. "It may be one in a million, but if it's you [with the allergy], it's 100%," he told MedPage Today.
He also noted that allergies now recognized as common were initially noticed in a single patient, with latex allergy being an example.
"When latex was first reported as an allergy, it was an abstract and it was forgotten for years. All of a sudden it became a signal when HIV came and this was a big issue. Having had that as a prior report allowed us to move forward," Oppenheimer said.
"What might be wacky today might be an epidemic tomorrow," he added.
With that in mind, here's a sample of some of the more unusual reports presented at this year's meeting.
Semen Allergy Explains Flu-Like Symptoms
Againdra Bewtra, MBBS, of Creighton University in Omaha, Neb., and colleagues described the case of a man who complained of head and body aches, accompanied by what he called "brain fog," within a day after ejaculation irrespective of the circumstances.
Bewtra's group had previously identified semen allergy in a series of female patients and, since there was no ready explanation of the man's symptoms, they tested him with a sample of his semen.
Skin prick testing with the sample yielded "mildly positive" results and a follow-up with intradermal testing showed a large reaction, the researchers reported.
They recommended that the man try prednisone and/or high doses of antihistamines before having sexual activity, but they did not indicate whether or not it worked.
Peanut Allergy in an Exclusively Breastfed Infant
Researchers at the University of Michigan in Ann Arbor reported what they believed to be the first case of enterocolitis triggered by peanut allergy in an infant whose only exposure appeared to be breast milk from his mother.
The case involved a 7-month-old who would vomit copiously after breastfeeding, but only when his mother had recently eaten peanut products. As far as could be determined, the baby boy was exclusively breastfed and had never eaten any peanut products directly.
Patch testing indicated peanut sensitivity, although skin prick and serum IgE results were negative for peanut. Oral challenge testing was not performed.
When peanut products were eliminated from the mother's diet, the baby's symptoms disappeared, according to David Robertson, MD, MPH, and Matthew Greenhawt, MD.
Although development of peanut allergy in this way appeared unprecedented, the researchers noted that previous studies had shown that breast milk can contain peanut protein and that other types of food allergies have been induced in exclusively breastfed infants.
Another Way Alcohol Can Be Bad for You
Alcohol not only ruins the liver and causes accidents, it also can be an allergen, according to researchers at Walter Reed National Military Medical Center in Bethesda, Md.
They described a case involving a 25-year-old woman who would develop hives on her back whenever she had alcoholic beverages, including wine, beer, and distilled spirits.
An oral challenge test at Walter Reed reproduced the syndrome, reported Wayne Wolverton, DO, and colleagues, and no recurrence was reported after they recommended strict avoidance.
The researchers said this was only the second reported case of systemic dermatitis attributed to ethanol allergy.
Anaphylaxis in an Allergy Clinic Worker
Needlesticks are hazardous even in the absence of contamination with infectious pathogens, according to another group of military doctors, who reported a case of anaphylaxis in a careless allergy clinic worker.
The worker was preparing syringes to be used for routine immunotherapy injections. She accidentally pricked herself with one containing Timothy grass allergens.
She was known to be mildly allergic to Timothy grass and had previously taken loratadine for it, but severe hypersensitivity had not been suspected.
Within five minutes of the needlestick, she developed a systemic reaction. It took five doses of epinephrine to bring her hypotension, tachycardia, and breathing difficulties under control, according to Capt. Michelle Bandino, MD, and Michael Tankersley, MD, of Lackland Air Force Base in San Antonio.
Post hoc review disclosed that the worker was also taking a beta-blocker, which is known to increase the risk of severe allergic reactions in sensitive individuals.
The Lackland physicians suggested that healthcare workers be screened for such risk factors before being assigned to duties that could expose them to potential anaphylaxis triggers.
Pork-Cat Syndrome: No Longer the French Disease
An odd co-allergy to pork meat and to cats previously reported only in France has now been detected in the U.S., according to a report from researchers at the University of Virginia.
In a platform presentation at the ACAAI meeting, Jonathon Posthumus, MD, said his clinic had confirmed "pork-cat" syndrome in six patients.
The condition appears to involve cross-reactive sensitivity to serum albumin from pigs and cats. In the case of cats, the protein is contained in skin and saliva, so the exposure is similar to that responsible for the more common cat allergy related to the Fel d1 protein.
Objective testing in the six patients showed that they were sensitive to cat and pork serum albumins.
Posthumus said a complicating factor in diagnosing the condition was that patients reported that reactions were inconsistent following pork ingestion. However, albumin proteins can be broken down by heating, so that different cooking methods could explain the variability.
About That Runny Nose ...
Two case reports here described patients whose rhinitis turned out not to be allergic, but something potentially far more serious.
Both patients complained of runny noses that did not appear correlated with any known allergen, either temporally or in objective testing.
Finally, physicians examined the nasal discharge itself and found that it was not the normal type, but in fact was cerebrospinal fluid. Follow-up imaging exams revealed fistulas through which CSF was leaking into the nasosinus cavity.
The two reports offered different tips on how to distinguish the condition from allergic rhinitis.
Richard Harris, MD, in private practice in Beverly Hills, Calif., noted that CSF contains glucose whereas normal nasal secretions do not. He suggested that urinary glucose test strips meant for monitoring diabetic patients can be used to determine that a nasal discharge is likely to be CSF.
The other group, led by Rohit Divekar, MD, PhD, of the University of Texas Medical Branch in Galveston, said that cranial CT findings were reliably diagnostic.
"An empty sella is a robust radiographic marker and is almost universally present in this group of patients, but not in patients with nonspontaneous leaks," they indicated.
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