Ariana Grande was forced to cancel two shows in Florida recently, for a very unusual reason.

It turns out the 25 year-old singer had an unexpected allergic reaction – to tomatoes.

“Update: we discovered … that … i had an unfortunate allergic reaction to tomatoes and my throat pretty much closed. still feels like i’m swallowing a cactus but slowly making progress!” she told fans via Instagram.

While we keep hearing about kids and their food allergies, the truth is, you can also develop such allergies when you’re an adult.

What the…?

Yep, it’s true. And it’s not that uncommon, either.

According to research, nearly half of all food-allergic adults had at least one adult-onset food allergy.

So, even if you could eat everything when you were a kid, doesn’t mean it’s necessarily going to be smooth sailing from there on in. Damn.

How do I know if I’m having an allergic reaction to food?

Allergic reactions to food usually develop soon after eating.

It can occur within a few minutes, or can take up to a couple of hours for symptoms to develop.

Those symptoms can include a tingling or itching sensation in the mouth, with or without swelling of the lips, tongue, face or throat.

You may also break out into hives (a rash), eczema or feel itchy.

An allergic reaction can also cause you to find it difficult to breathe and you may develop wheezing, or nasal congestion.

You may feel nauseous, start vomiting, feel dizzy or lightheaded, develop a stomachache, or even faint.

Who’s most likely to get it?

Food allergies tend to be more common in people who have a family history of allergies, eczema, hives or hay fever.

Also, if you’re allergic to one food, you may be at increased risk of being allergic to another.

Having asthma also puts you at greater risk of having a food allergy.

Why do they happen?

When you eat a food you’re allergic to, your immune system mistakenly identifies it to be harmful. It then releases something called IgE antibodies in response.

So, next time you eat even a tiny bit of that food, in comes those IgE antibodies, and they signal your body to release chemicals including histamine into your blood.

Those chemicals cause those nasty allergic symptoms.

What should I do if I think I’m having an allergic reaction?

In the cases of mild allergy, medications such as antihistamines can help.

If you think you’re having a mild allergic reaction, it’s best to do what Ariana did, and see a doctor.

If you already know you have a food allergy, make sure you try to avoid eating that food by carefully reading labels.

Talk to your doctor about the best management plan for you.

Unfortunately, allergic reactions can be very serious, and may even be life-threatening.

A severe, life-threatening allergic reaction is known as anaphylaxis.

Symptoms of anaphylaxis can include feeling like your throat is closing over and that you’re struggling to breathe.

Your blood pressure can drop and your heart can race, and you can feel dizzy or lightheaded, and may lose consciousness.

If you think you’re having an anaphylactic reaction, you need urgent medical care.

As for Ariana, it seems like – from a health-perspective, at least – she’s recovering well from her allergic reaction.

But she is upset about something else.

As she wrote on her original post: “there is NOTHING MORE UNFAIR THAN AN ITALIAN WOMAN DEVELOPING AN ALLERGY TO TOMATOES IN HER MID TWENTIES”.