Will babies have a fever if they have food allergies?

Most common food allergies will not directly cause fever, but a few severe allergies, or allergic reactions combined with mucosal damage and secondary infection, will indeed cause an increase in body temperature. Currently, there is no unified conclusion in the academic community on whether simple food allergies can directly cause fever.

Last week, I saw an 11-month-old girl. Her mother touched a mango for the first time to her. She took two bites and her mouth immediately turned red. Within half an hour, there were wheals all over her body, and she was crying and having diarrhea. When she came to the clinic, her armpit temperature was 37.9°C, and her fingertip blood count was completely normal. There were no cold symptoms such as runny nose or cough, so I was prescribed age-appropriate anti-allergy drops. After I drank it at home, the rash gradually disappeared, and the body temperature dropped to 36.8°C in less than 3 hours. The child’s mother was quite surprised, saying that she had always thought allergies were rashes, and she didn’t expect to have a fever.

I have also discussed this controversial point when communicating with colleagues before. Many doctors insist that simple allergies are just immune globulin-mediated stress reactions and will not affect the temperature regulation center. Any fever must be combined with other problems - for example, some babies frequently vomit after eating allergenic foods, and the throat mucosa is damaged. Bacteria invade and cause inflammation, or the immunity is temporarily disturbed during allergies and the latent cold virus happens to be encountered. However, the time is close, and everyone mistakenly thinks that it is a fever caused by allergies.

However, in the clinical cases I have compiled over the years, it is true that nearly 10% of the children, like this girl who ate mangoes, showed no signs of infection. Their body temperature returned to normal as soon as the allergic symptoms subsided. Therefore, more and more clinical workers now also classify this transient low-grade fever as an accompanying manifestation of severe allergies. However, the temperature of this kind of fever is generally not too high, basically below 38.5°C, and the duration rarely exceeds 12 hours.

Everyone should be more careful when adding new complementary foods to their babies. It is best to add a single food and observe it for 3 days before changing to new varieties. If the baby develops rash, diarrhea, frequent rubbing of eyes and nose, allergies, and a low fever after eating the new food, do not rush to give him anti-inflammatory and antipyretic drugs first. Stop the suspected allergenic food, feed more warm boiled water, and observe the physical cooling first. If the fever exceeds 38.5°C, or the child becomes weak, has shortness of breath, or has more rashes on the body, don’t hesitate to go to the hospital quickly. It is most likely not a simple allergy problem, so don’t delay diagnosis and treatment.