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What scientists know about the itch-scratch cycle in atopic dermatitis
Learn how skin barrier damage, inflammation, and nerve signaling work together to drive the itch-scratch cycle in atopic dermatitis and eczema.
For many people with atopic dermatitis, commonly known as eczema, itching can be one of the most challenging symptoms to manage. The urge to scratch may feel impossible to ignore, especially during the flare-ups or at night. Unfortunately, scratching often makes symptoms worse, creating what researchers call the itch-scratch cycle.
This cycle is one of the defining features of atopic dermatitis, a condition that many people experience as a part of a larger autoimmune issue. Scientists now understand that it involves much more than dry skin alone. A complex interaction between the skin barrier, the immune system, and the nervous system helps drive chronic itching and repeated scratching. Understanding how these symptoms work together may help explain why atopic dermatitis can be so persistent.
What is the itch-scratch cycle?
The itch-scratch cycle describes a self-perpetuating process in which itching leads to scratching, and scratching leads to even more itching. At first, an itch may develop because of inflammation, dry skin, an environmental trigger, or skin irritation. Scratching provides temporary relief, but it also damages the skin. This damage triggers additional inflammation and activates itch-sensitive nerve fibers, creating stronger itch signals.
As the cycle continues, the skin becomes increasingly irritated and sensitive. Over time, even minor triggers may provoke significant itching, making it difficult to break the pattern. Researchers consider the itch-scratch cycle a central mechanism in atopic dermatitis because it contributes to both symptom severity and disease progression.
The skin barrier's role
Healthy skin acts as a protective barrier between the body and the outside environment. It helps retain moisture while keeping irritants, allergens, and microbes out. In atopic dermatitis, this barrier does not function as effectively as it should. Many people with the condition have changes in proteins that help maintain skin structure and hydration. As a result, the skin may lose water more easily and become dry, cracked, and vulnerable to irritation.
When the skin barrier is weakened, environmental triggers can penetrate more deeply into the skin. This exposure activates immune responses that contribute to inflammation and itching. Barrier disruption also increases sensitivity. Skin that is already inflamed may react more strongly to factors that would not bother someone without atopic dermatitis, such as fabrics, soaps, temperature changes, or sweat.
How the immune system contributes to itching
Inflammation plays a major role in the itch-scratch cycle. Atopic dermatitis is associated with an overactive immune response that promotes the release of inflammatory signaling molecules. These immune signals help drive many of the symptoms associated with eczema, including redness, swelling, and itching.
Researchers have identified several cytokines that appear to be particularly important in atopic dermatitis. Some of these inflammatory molecules can directly stimulate itch pathways, making the sensation stronger and more persistent. This helps explain why itching often continues even when there is no obvious external trigger. The immune system itself may be generating signals that promote itch sensations.
As inflammation increases, scratching causes additional skin damage, which in turn triggers further immune activation. This creates a feedback loop that reinforces the cycle.
The nervous system and chronic itch
One of the most important discoveries in recent years is the role of the nervous system in chronic itch. The skin contains specialized nerve fibers that detect itch sensations and send signals to the brain. In atopic dermatitis, these nerves may become unusually sensitive.
Research suggests that inflammation can change how itch-sensitive nerve fibers function. Certain inflammatory molecules increase communication between immune cells and sensory nerves, amplifying itch signals before they reach the brain.
Scientists have also observed increased nerve growth in affected skin. As more nerve fibers develop near the skin's surface, the skin may become more responsive to itch triggers. This heightened sensitivity helps explain why chronic itch can persist even when visible inflammation improves. The nervous system itself may remain primed to react.
Why scratching feels good, at least temporarily
Many people wonder why scratching provides relief if it ultimately worsens symptoms. Researchers believe scratching activates pain-related nerve pathways that temporarily override itch signals. This interruption can create a brief sense of relief and satisfaction.
The brain may also release reward-related neurotransmitters during scratching, reinforcing the behavior. In other words, scratching can feel rewarding in the moment, even though it contributes to long-term symptoms.
Unfortunately, the relief is usually short-lived. Once scratching damages the skin and inflammation increases, itch signals often return even stronger than before.
Why the itch-scratch cycle can be hard to break
The itch scratch cycle involves multiple biological systems working together. A weakened skin barrier allows irritants to enter. The immune system responds with inflammation. Inflammatory signals activate itch-sensitive nerves. The nervous system amplifies those signals and sends them to the brain. Scratching then causes additional skin damage, restarting the process.
Since so many mechanisms are involved, there is rarely a single trigger or solution. Factors such as stress, poor sleep, environmental allergens, heat, and infections can also intensify symptoms and make itching harder to control. This complexity helps explain why managing atopic dermatitis often requires addressing several aspects of the condition at the same time.
Managing your symptoms with Evidation
Scientists now recognize that the itch-scratch cycle in atopic dermatitis is driven by an ongoing interaction between skin barrier dysfunction, immune system activity, inflammation, and nerve signaling. What starts as an itch can quickly become a self-reinforcing cycle that is difficult to stop.
As research continues to uncover how these systems interact, tracking symptoms, triggers, and flare patterns can help you better understand your health. With Evidation, you'll get to use the health data you're already tracking to find patterns and get insights that can help you make decisions that take your health and well-being in the right direction. Click here to learn more about Evidation and get started today.
Can sleep patterns tell us the severity of our anxiety or depression?
Depression and anxiety can have a huge impact on our daily lives and overall health. It can affect our mood, social interactions, sleep and more, but can our daily behaviors predict the severity of our anxiety and depression? Our research team sought to find out more.
We know that anxiety and depression affect many of you, with 7 out of 10 adults in the U.S. saying they experience stress or anxiety daily. Depression and anxiety can have a huge impact on our daily lives and overall health. It can affect our mood, social interactions, sleep and more, but can our daily behaviors predict the severity of our anxiety and depression? Our research team sought to find out more.
What we tested
We enrolled over 1,000 participants in a clinical study with self-reported anxiety and depression and assessed the participants’ mental health states by looking at the following for each individual:
- Anxiety and depression symptoms
- Number of hospitalizations and ER visits for anxiety/depression
- Use of anxiety and depression medications
We then looked at participants’ sleep metrics and patterns for the previous three months.
What we learned
Severe depression was significantly associated with inconsistent and disordered sleep patterns, such as spending a great amount of time in bed awake. Individuals taking medications for their anxiety and/or depression were likely to sleep more compared to those not receiving treatment, however, they also had inconsistent sleep patterns. Participants who had been previously hospitalized for anxiety and/or depression were more likely to have inconsistent sleep patterns as well.
What does this mean?
We all know that a lack of sleep can affect our daily lives, but it can also be associated with severe depression and anxiety. This means that certain sleep patterns might be able to predict the severity of an individual’s mental well-being in the future. With further research we’d like to understand if tracking sleep behavior could predict changes in the severity of an individual’s mental health condition.
Thanks to all of our members who participated in this research about how daily behaviors, like sleep, can tell help researchers to better understand anxiety and depression. If you’re interested in contributing to innovative research, we are regularly running new studies at Evidation.
3 Reasons Why Tracking Your Health Can Help You Participate in Better Health Outcomes
Here are the top three reasons why tracking your health with Evidation will help you be part of something just a little bit bigger than yourself this holiday season.
According to 2015 Pew Research, “one in three cell phone owners have used their phone to look for health information.” Four years ago, we started Evidation to help everyone understand their personal health, take control of their health journey, and help contribute to improving the health of everyone. Here are the top three reasons why tracking your health with Evidation will help you be part of something just a little bit bigger than yourself this holiday season.
1. Actively participate in your health
With the over 30+ apps that you can connect to Evidation, we’re able to look at patterns of activity levels and do a deep dive into tracking health and wellness. We’ve published research around how your social engagements can impact activity levels. Lastly, we’ve given our community a chance to learn from each other, asking communities of individuals what questions they have for one another and sharing back the results.
2. Learn about health and research through insights
With a community of over a million, we’re constantly looking for opportunities to highlight and share relevant research tailored to you. We’ve also done deep dives on seasonal trends over the last year, including a step analysis around the Pokemon Go phenomenon, the difference between men and women during Back to School, and a look across the United States at Halloween calorie count.
3. Participate in ground-breaking research to advance the health of everyone
We’re focused on building a product that makes your interactions with health unified. We believe that health is much more than a visit to the doctor. It’s a constant effort every day of how to track/monitor healthy activities — whether it be steps taken, heart rate monitored, sleep tracked, or even meditation sessions executed. Sign up for Evidation today and starting taking health-related actions, including contributing to cutting-edge clinical studies that are tailored to your specific health conditions.
Dads vs. Moms: How does the transition from summer to fall impact activity levels?
The change in seasons often brings with it a change in routine. We wanted to know how the transition from summer to fall affects our health and wellness, and we’re excited to share these insights from members.
The change in seasons often brings with it a change in routine. So we wanted to know how the transition from summer to fall affects our health and wellness, and we’re excited to share these insights from Evidation Members.
The transition to fall can be especially cumbersome for parents as they juggle back to school duties, but is one parent more impacted than the other by the changing season? We decided to take a closer look at how moms and dads health holds up during the seasonal transition. We were also curious to explore how sleep and steps between parents and non-parents compared.
Who is catching more zzzs?
We uncovered a statistically significant gender disparity between moms and dads. Moms sleep 5 minutes less in the summer than their non-mom counterparts. As the school year ramps up in late August and early September, the difference is significantly more pronounced on weekdays. Moms sleep 10 minutes less than their non-mom counterparts. Dads, on the other hand, show no consistent differences from their counterparts in summer or fall. If anything, they may sleep slightly more.
Moms are also taking a bigger hit in sleep interruption than Dads. Moms sleep 0.34% less than non-moms and 1.4% less than dads. Surprisingly though, non-dads have the most sleep interruptions, spending 8.3% of the night awake.
What time is everyone falling asleep?
Moms fall asleep 12 minutes earlier than non-moms, while dads fall asleep 24 minutes earlier than non-dads. So, while dads don’t seem to be sleeping any less if they are a parent, they appear to be shifting their sleep schedules more. Interestingly, all four groups shift their bedtimes earlier in fall, possibly due to earlier sunsets.
Who is taking more steps?
Moms take fewer steps than non-moms in general. During the summer, moms take 427 fewer steps/day on weekends and 243 fewer steps/day on weekdays. However, when the school year starts, their weekends show an even larger deficit, at 543 fewer steps/day vs non-moms. Their weekdays step counts improve markedly, though, at just 85 fewer steps/day than non-moms.
Dads show the opposite pattern. They actually take more steps than non-dads. In the summer, they have an average of 250 steps/day more than non-dads, while in the fall, they have an average of 348 steps/day more than non-dads.