A two-and-a-half-year-old Pennsylvania girl did something unremarkable while at a Walmart—and it almost killed her. The girl ate a mandarin orange while in the store; after experiencing itching and swelling, her parents gave her a dose of Benadryl, but her condition worsened, with coughing and spasming lungs.

She was having a potentially deadly anaphylactic reaction, which a co-author of a new paper about the case explains occurs when multiple organs are affected by an allergen.

A shot of epinephrine is generally administered in these cases; it eases swelling and helps to open airways. Newsweek reports that the toddler required two shots, and then needed to be hooked up to a ventilator for a short time.

Doctors were initially stumped. Her parents insisted that the 31-month-old ate only the orange before having the reaction, but oranges rarely cause an allergic reaction to begin with, and when they do, that reaction is usually mild.

A press release also notes that the toddler had previously drunk orange juice without issue. Doctors eventually verified an orange was to blame after conducting a skin-prick test, and established she also had a peach allergy.

It's the first known case of a severe anaphylactic reaction to the fruit, according to an allergist who points to a protein found in oranges that has a chemical makeup similar to pollen as the likely culprit.

The girl was also diagnosed with asthma, which likely worsened the issue; 90% of kids with asthma also experience allergies. (A recent study found that what we do to peanuts may cause allergies.)

This article originally appeared on Newser: Toddler Almost Dies From Nearly Unheard-of Allergy

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