Skin water loss predicts anaphylaxis in food allergy tests

TEWL increase precedes food anaphylaxis and predicts challenge results.


Food allergies can be really dangerous, turning a simple meal into a life-threatening situation. Every year in the United States, about 200,000 people end up in the emergency room due to a severe allergic reaction called anaphylaxis. This reaction can include a skin rash, nausea, vomiting, difficulty breathing, and shock. Since figuring out a food allergy is crucial for life and death, getting an accurate diagnosis is very important.

The usual way to diagnose a food allergy is through oral food challenges. In these challenges, patients eat increasing amounts of the suspected food allergen under the supervision of a medical provider. This method is more accurate than skin and blood allergy tests, which often give wrong results. However, there’s a risk of anaphylaxis during these challenges, making it necessary for patients to have an epinephrine injection on hand.

The University of Michigan researchers created a way to predict anaphylaxis during oral food challenges by measuring skin water loss before it shows clear symptoms. Published in The Journal of Clinical Investigation, this method could improve safety and comfort for patients by detecting anaphylaxis earlier, reducing the need for emergency measures like epinephrine, according to lead author Charles Schuler, M.D., an immunologist at Michigan Medicine.

During anaphylaxis, blood vessels widen, causing increased heat and water loss from the skin. Previous research explored using facial thermography, which requires specialized equipment and controlled conditions, making it impractical, especially for children with food allergies.

The researchers, however, confirmed the effectiveness of measuring transepidermal water loss. This measurement, representing the amount of water escaping from a given skin area per hour, proved reliable in detecting anaphylaxis compared to biochemical and clinical observation methods.

Transepidermal water loss increased during food allergy reactions and anaphylaxis. Notably, this rise correlated with biochemical markers of anaphylaxis and occurred well before the clinical detection of anaphylactic symptoms.

Schuler said, “Transepidermal water loss measurement can be done in an office without specialized equipment, affixed to the skin and worked in children, making it a vast improvement from previous attempts at early anaphylaxis detection methods.”

Schuler’s research team is looking for kids aged six months to 5 years to join a trial called “Predicting Peanut Anaphylaxis and Reducing Epinephrine.” In this study, they’re monitoring water loss from the forearm during a peanut allergy test. The goal is to figure out specific values linked to anaphylaxis so they can establish rules to stop the test, potentially lessening the need for epinephrine injections. This could make peanut allergy testing safer for young children.

Measuring transepidermal water loss is a promising method for predicting anaphylaxis during food allergy tests. If successful, this approach could enhance patient safety by providing an early indicator of anaphylactic reactions facilitating timely and appropriate interventions during oral food challenges.

Journal reference:

  1. Charles F. Schuler IV, Kelly M. O’Shea et al., Transepidermal water loss rises before food anaphylaxis and predicts food challenge outcomes. The Journal of Clinical Investigation. DOI: 10.1172/JCI168965.
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