Atopic dermatitis, or eczema, is a common skin condition affecting around one in five children. It can cause sufferers to itch so badly that they stay awake at night scratching causing them to lose, on average, a full night’s sleep per week.


Itching, however, is a difficult symptom to measure, making it tricky to track how effective any drugs and treatments being administered are.

Now, researchers at Northwestern University have developed a soft skin patch capable of measuring how often its wearer scratches themselves.

The patch consists of a soft, flexible sensor that fits around the patient’s hand that is linked up to machine learning algorithms that specifically identify scratching without being tricked by similar motion-related movements such as hand waving. It is the first sensor that is capable of capturing all forms of scratching whether the movement comes from the finger, wrist or elbow.

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“Atopic dermatitis is so much more than just itchy skin. It is a devastating disease that causes tremendous suffering worldwide. The quality of life of severe atopic dermatitis (not only for the child but also the parent) is equivalent to many life-threatening diseases,” said lead author Dr Shuai “Steve” Xu, assistant professor of dermatology and of paediatrics at Northwestern University Feinberg School of Medicine.

“Patients with atopic dermatitis are 44 per cent more likely to report suicidal thoughts as a result of the itch compared to controls. Thus, the ability to quantify their symptoms is really important to help new drugs get approved, but also support their day to day lives. In some ways — it's like measuring glucose for diabetes...measuring itching in an atopic dermatitis patient may be just as important.”

First, the team trained the sensor to pick up scratching in healthy adults as they performed specific scratching behaviours. They then tested the sensors on children with atopic dermatitis, logging more than 300 hours of sleep data.

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“This is an exciting time for children and adults with atopic dermatitis — or eczema — because of the flurry of activity in developing new therapeutics,” said Dr Amy Paller, chair of dermatology at Northwestern. “Nothing is more important to measure a medication's effectiveness for eczema than itch, the symptom that both defines eczema and has the greatest impact on quality of life. This sensor could play a critical role in this regard, especially for children.”


Jason Goodyer
Jason GoodyerCommissioning editor, BBC Science Focus

Jason is the commissioning editor for BBC Science Focus. He holds an MSc in physics and was named Section Editor of the Year by the British Society of Magazine Editors in 2019. He has been reporting on science and technology for more than a decade. During this time, he's walked the tunnels of the Large Hadron Collider, watched Stephen Hawking deliver his Reith Lecture on Black Holes and reported on everything from simulation universes to dancing cockatoos. He looks after the magazine’s and website’s news sections and makes regular appearances on the Instant Genius Podcast.