A sudden allergy to tomatoes in your twenties? Is that even a thing? According to Ariana Grande it is, as the singer was forced to postpone a pair of Sweetener World Tour shows in Florida this week due to "an unfortunate allergic reaction to tomatoes" that she said closed up her throat and made it feel like she was swallowing cactus.

To find out more about this unusual condition, Billboard spoke to board-certified allergist/immunologist Katie Marks-Cogan, who specializes in food allergies. Speaking as an expert with no direct knowledge of Grande's case, Marks-Cogan says that while food allergies are more common in children, you can develop food allergies at any age. "A recent study in the Journal of the American Medical Association based on a survey showed that 10 percent of adults likely have a food allergy and about 27 percent of them never had a food allergy as a child and only developed one as an adult," she says, noting that the figures were a bit higher than experts expected.

"We know that you can develop a food allergy at any time and that plenty of adults eat foods their whole life but then develop an allergy," Marks-Cogan adds. She says those seemingly sudden allergies could be caused by environmental or hormonal factors, or caused by something called Pollen Food Syndrome, which occurs when the immune system gets confused and thinks proteins in fresh foods and vegetables look like pollen from trees and grasses.

"When you have an allergy you are actually allergic to a protein, and proteins in certain fresh fruits and vegetables look very similar to the body to the proteins in pollen," she explains. "So when you eat a tomato, the immune cells in your mouth think, 'Oh, this is grass pollen.' And because they're trying to protect you from grass pollen that you may be allergic to, they release histamine to fight it off." That release can cause localized itching and swelling of the mouth, tongue and throat such as that described by Grande, and, in very rare cases a more serious, larger systemic reaction."

The type of reaction Grande appears to have had is more common with raw fruits and vegetables, Marks-Cogan says, as cooking tomatoes and other fresh produce breaks down and denatures the potentially troublesome proteins.

"Oral allergy syndrome is probably more common than we think," she says, but "very few" adults are likely to develop a full-blown tomato allergy. Especially because eight foods or food groups make up 90 percent of all food allergies, including milk, eggs, peanuts, tree nuts, soy, shellfish, fish and wheat, and, in an emerging concern, sesame allergy.

Grande's unexpected allergic reaction, which she joked in all caps was, "NOTHING MORE UNFAIR THAN AN ITALIAN WOMAN DEVELOPING AN ALLERGY TO TOMATOES IN HER MID TWENTIES," led to the postponement of Tuesday night's show at the Amalie Arena in Tampa and Wednesday night's gig at the Amway Center in Orlando. Those shows have been rescheduled for, respectively, Nov. 24 and Nov. 25. At press time Grande was expected to resume the tour on Friday night (May 31) at the AmericanAirlines Arena in Miami.