In 2014, a trio of concerned doctors wrote a letter to the editor of Allergologia et Immunopathologia, a Spanish scientific journal concerning allergies. They wanted to alert the scientific community to a potential danger: lion allergies.
It all started when an 8-year-old boy came into their emergency department in Warsaw, Poland.
"He came along with his parents, directly from a circus show," the doctors wrote. "About 30–45 min after the beginning of the show, he started complaining of itching skin and a burning sensation in his eyes, followed by rhinorrhea [runny nose]. The symptoms occurred a few minutes after the first animals appeared on stage."
These doctors speculated that the child — who tested positive for cat allergies — was also allergic to the cats in the circus. "The symptoms suddenly arose when the lion-taming begun," the doctors wrote.
They were especially concerned that the same warnings that doctors give about cat allergies were not extended to lions. "Recommendations for avoiding [house cat] allergens do not include any restrictions of contact with big cats in places like Wild Parks, Zoos or circus visits." Perhaps they should.
If you're allergic to house cats, you're probably allergic to lions and tigers too
Granted, if you're trapped in a room with one of these carnivorous animals, sneezing will be the least of your concerns.
Still, it's a good question: Why would someone allergic to house cats also be allergic to a lion?
Because all cats shed dander — a.k.a. dead skin cells.
With house cats, it's often a single protein in that dander, called "Fel d 1," that causes allergies and gets eyes watering. Fel d 1 is secreted in cats' saliva and skin. When a cat grooms, cells containing Fel d 1 become airborne and will irritate those sensitive to it.
And at least one published paper suggests big-cat dander may also contain Fel d 1, or a protein similar enough to provoke an allergic reaction. (Admittedly, there's not a lot of research on this.)
The 1990 study, published in the Journal of Allergy and Clinical Immunology, tested the dander of eight species of felines: ocelots (obviously the coolest), pumas, servals, Siberian tigers, lions, jaguars, snow leopards, and caracals (a.k.a. desert lynx).
The researchers then exposed 11 people with allergies to the exotic cat dander. (An additional five people allergic to mites, five people without any allergies, and four zoo employees who work with big cats served as study controls.)
The conclusion: In general, those with cat allergies also showed an allergic response to the big-cat dander, but it wasn't as strong. (Participants showed the weakest reaction to the caracal, in case you're worried about a zoo trip.)
The study also found that this mild big-cat allergy didn't usually affect the patients' lives. Except, that is, for "the second patient, [who] avoided visits to a zoo or circus show."