Novel Device Promises Safer Oral Food Allergy Challenges

For patients, especially children, undergoing an oral food challenge is the only definitive way doctors can confirm a suspected food allergy. This process involves giving a patient the potentially allergenic food in a controlled setting to observe for a reaction. However, as Charles Schuler, MD, an allergist at Michigan Medicine, explains, this procedure is “unpleasant, doesn’t feel good, it’s potentially risky and it’s very expensive,” requiring significant logistical support and time. This inherent risk often makes parents and patients hesitant to proceed.

A team led by Schuler has been working to address the risks associated with food allergy challenges. Their efforts led to the development of a novel device named TEWL, which stands for transepidermal water loss. This device accurately measures water loss from the skin, a physiological change known to occur rapidly during an allergic reaction, specifically anaphylaxis, a finding they observed in a previous study. The potential of this technology lies in its ability to provide an objective, real-time indicator of a developing allergic response.

The team recently published a pilot study in JAMA Open Network detailing the use of TEWL during live food allergy challenges. The core question was whether combining the objective TEWL measurement with the presence of just one additional allergic reaction symptom (such as sneezing, an itchy mouth, or a single hive) could serve as a reliable stopping criterion. The goal was to halt the challenge early enough to prevent the progression to a severe allergic reaction or anaphylaxis, all while maintaining the accuracy of the diagnostic process.

The non-invasive TEWL monitor is easily placed on the forearm and requires no needles. It functions by measuring the rate of water loss (grams/square meter/hour) from the skin using sensitive humidity and temperature sensors. Schuler explained that when this rate suddenly increases, an allergic reaction is likely imminent. By pairing this objective numerical finding with a single observed symptom, clinicians could stop the challenge at a critical point where severe reactions were largely avoidable for many participants.

The pilot clinical trial focused on children aged 5 and under, a particularly important demographic because their limited expressive language makes it challenging for allergists to interpret their symptoms during a food challenge accurately. The researchers needed an “objective and external way to observe what’s happening inside their bodies,” according to Schuler. The children readily wore the device, confirming its ease of use.

The study successfully demonstrated the device’s utility by comparing TEWL measurements taken two minutes before a peanut dose to those taken two minutes after consumption. In participants heading toward a reaction, a distinct difference in the skin’s water retention was observed. Crucially, when the team used this monitored change, along with one objective symptom (such as a runny nose or a hive), as the signal to stop the challenge, they found a significant decrease in the overall severity and symptoms of the reaction, with most participants avoiding the need for epinephrine or other significant interventions.

Based on these results, which showed a significant decrease in reaction severity according to multiple international grading criteria, the research group is now planning the next step: seeking funding to develop an evolved, wireless version of the TEWL device. This new version would feature a user-friendly interface, making it easily usable in various clinical environments beyond Michigan Medicine, ultimately improving the safety and accessibility of food allergy challenges globally.