Ariana Grande postpones world tour after allergic reaction to tomatoes

Ariana Grande will be postponing shows in her “Sweetener World Tour” after experiencing an allergic reaction to tomatoes, the singer reported in a Wednesday post to Instagram.

Describing her reaction, the 25-year-old former Nickelodeon star wrote “my throat almost closed” and it “still feels like I’m swallowing a cactus.”

So how unusual is it for an adult to develop a food allergy?

About 10% of American adults — 26 million people — have a food allergy, according to Dr. Ruchi Gupta, director of the Science and Outcomes of Allergy and Asthma Research Program at Northwestern Feinberg School of Medicine. While half of these — 13 million adults — developed a new food allergy later in life, only about 1 in 4 never had any type of food reactions during childhood and then developed one as an adult.

Importantly, most adults in Gupta’s survey of more than 40,000 people had never seen a doctor about their reaction, she said — they just started avoiding the food. So while 1 in 10 adults have an actual food allergy, only 1 in 20 get a proper diagnosis.

“It’s really critical that if something does happen when you eat a food that you see an allergist,” she said, explaining that there are a lot of different conditions, including intolerances and oral allergy syndromes, that are not true food allergies. A reaction to tomatoes, for example, can actually be an “oral allergy syndrome if you have environmental allergies like grass allergy,” she said. Oral allergy syndrome can also cause itching, tingling or swelling in or around the mouth.

On the other hand, a true food allergy can cause severe symptoms in many organ systems, such as hives, itching, swelling, throat closing, trouble breathing, wheezing, vomiting and a drop in blood pressure.

A food allergy can be severe and life-threatening, said Gupta. “If it is a true food allergy, then you want to have a management plan, an action plan, and you want to carry an epinephrine auto-injector in case you have a severe reaction. It’s important to have that with you in case of an emergency.”

Gupta said she conducted the survey because “I just kept hearing about adults who developed allergies later in life. This was really eye-opening for me — the fact that so many adults have a food-related condition.”

So why can some adults eat a food their entire lives and then one day have a reaction?

“That big ‘why’ is a very, very important question that we’re focusing on in our lab,” said Gupta, who explained the exact trigger for adult allergies has not yet been found.

“Some of the things we think about are, were there any environmental changes? Did you move from one town to another?” Other theories include the possibility that a viral or bacterial illnesses could have influenced a person’s immune system. A prescribed antibiotic also might also have changed the immune system. Finally, hormonal changes can have an impact, as well.

Gupta is currently analyzing the answers given by adults with allergies in her survey. “We need to at least see what people are telling us to better understand,” she said.

So how many people share a tomato allergy with Grande?

“Tomato allergy is not one of the top nine adult food allergies,” said Gupta. The top allergies in adults are shellfish, milk, peanuts, tree nuts, fin fish, wheat, soy and sesame.

Gupta wishes Grande well, believing the singer will undoubtedly receive the care she needs.

Grande has much to be thankful for: Recently she was selected to be the face of Givenchy’s 2019 Fall and Winter campaign scheduled to launch in July. In April she became the youngest singer to headline Coachella.

Still, fate awaited her in the form of a juicy, red fruit. There is “nothing more unfair than an Italian woman developing an allergy to tomatoes in her mid twenties,” Grande wrote on Instagram.

CNN’s Mallory Hughes contributed to this article.