Cracks in the skin of eczema patients promote allergic diseases

Infants who develop eczema are more likely to develop food allergies, hay fever and asthma as they grow older, a progression known as the atopic march. Donald Leung, MD, PhD, head of Pediatric Allergy & Clinical Immunology at National Jewish Health, has identified itching and dry cracked skin of eczema patients as a significant promoter of the atopic march. Moisturizers, especially early in a child's life, may help prevent eczema, food allergies and other allergic diseases.

"When food particles are introduced through the skin rather than the digestive system, they are much more likely to cause allergies," said Dr. Leung. "Cracks in the skin of those with eczema often set off a chain of allergic diseases that develop over several years."

Seventeen-year-old Ava Segur experienced the atopic march first hand. It started with eczema when she was just six weeks old. Her mother, Stephanie, says they were trying to get her skin inflammation under control, when they were suddenly confronted with another problem. "She had hives all over her arms and neck," she said. "So we took her to the hospital and found out she is allergic to peanuts, pine nuts and shellfish." A few years later, Ava developed exercise-induced asthma.

Ava has participated in numerous clinical trials seeking better treatments for eczema and a better understanding of the atopic march. "If we can find a solution that will work to stop this before it starts, it will be very rewarding to know that I was able to be a part of that," said Ava.

"Restoring the skin barrier as soon as eczema develops is the best way to stop the atopic march in its tracks and prevent allergic diseases from developing," said Dr. Leung.

The skin forms an important barrier, keeping moisture in and external allergens or microbes out. Research by Dr. Leung has shown that patients with eczema lack important proteins and lipids in the outer layers of their skin. As a result of eczema patients' defective skin barrier, water escapes from the skin, drying it out and leading to cracking and itching. Cracked, itchy skin is a hallmark of eczema.

Scratching the dry, itchy skin of eczema patients can further damage the skin barrier and activate the immune system. Increasing evidence compiled by Dr. Leung and others indicates that food particles entering the body through cracks in the skin can trigger an allergic response that leads to food allergy. Once that allergic response has been triggered, the immune system is primed to develop not only eczema and food allergies, but also hay fever and asthma.

To do this, experts recommend what they call "soak and seal," which involves thoroughly moisturizing the skin in a warm bath, then trapping the moisture in with a moisturizing ointment. It's a method Kriston Kline says helped her 19-month-old son's skin begin to heal within a week.

"It provided him with immediate relief, and each time we do a soak-and-seal treatment, his skin looks so much better," said Kline. "Not only is this making him more comfortable now, but if it can help protect him from allergies and asthma, that is a huge benefit for his future."

Dr. Leung believes that careful care of a baby's skin right from birth could prevent eczema and other allergic diseases. A baby's skin is particularly susceptible to drying out when it first emerges from the warm, watery environment of the womb into the dry air of the outside world. A few small studies have suggested that regular treatment with skin moisturizers can help reduce an infant's chances of developing eczema and the other diseases in the atopic march. Dr. Leung is currently working to confirm those studies and identify the ideal moisturizer components to prevent eczema and the other diseases of the atopic march.

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Materials provided by National Jewish Health. Note: Content may be edited for style and length.

Pig-Pen effect: Mixing skin oil and ozone can produce a personal pollution cloud

Ozone can produce a personal pollution cloud

When ozone and skin oils meet, the resulting reaction may help remove ozone from an indoor environment, but it can also produce a personal cloud of pollutants that affects indoor air quality, according to a team of researchers.

In a computer model of indoor environments, the researchers show that a range of volatile and semi-volatile gases and substances are produced when ozone, a form of oxygen that can be toxic, reacts with skin oils carried by soiled clothes, a reaction that some researchers have likened to the less-than-tidy Peanuts comic strip character.

"When the ozone is depleted through human skin, we become the generator of the primary products, which can cause sensory irritations," said Donghyun Rim, assistant professor of architectural engineering and an Institute for CyberScience associate, Penn State. "Some people call this higher concentration of pollutants around the human body the personal cloud, or we call it the 'Pig-Pen Effect.'"

The substances that are produced by the reaction include organic compounds, such as carbonyls, that can irritate the skin and lungs, said Rim. People with asthma may be particularly vulnerable to ozone and ozone reaction products, he said.

According to the researchers, who reported their findings in a recent issue of Nature's Communications Chemistry, skin oils contain substances, such as squalene, fatty acids and wax esters. If a person wears the same clothes too long -- for example, more than a day -- without washing, there is a chance that the clothes become more saturated with the oils, leading to a higher chance of reaction with ozone, which is an unstable gas.

"Squalene can react very effectively with ozone," said Rim. "Squalene has a higher reaction rate with ozone because it has a double carbon bond and, because of its chemical makeup, the ozone wants to jump in and break this bond."

Indoors, ozone concentration can range from 5 to 25 parts per billion -- ppb -- depending on how the air is circulating from outside to inside and what types of chemicals and surfaces are used in the building. In a polluted city, for example, the amount of ozone in indoor environments may be much higher.

"A lot of people think of the ozone layer when we talk about ozone," said Rim. "But, we're not talking about that ozone, that's good ozone. But ozone at the ground level has adverse health impacts."

Wearing clean clothes might be a good idea for a lot of reasons, but it might not necessarily lead to reducing exposure to ozone, said Rim. For example, a single soiled t-shirt helps keep ozone out of the breathing zone by removing about 30 to 70 percent of the ozone circulating near a person.

"If you have clean clothes, that means you might be breathing in more of this ozone, which isn't good for you either," said Rim.

Rim said that the research is one part of a larger project to better understand the indoor environment where people spend most of their time.

"The bottom line is that we, humans, spend more than 90 percent of our time in buildings, or indoor environments, but, as far as actual research goes, there are still a lot of unknowns about what's going on and what types of gases and particles we're exposed to in indoor environments," said Rim. "The things that we inhale, that we touch, that we interact with, many of those things are contributing to the chemical accumulations in our body and our health."

Rather than advising people whether to wear clean or dirty clothes, the researchers suggest that people should focus on keeping ground ozone levels down. Better building design and filtration, along with cutting pollution, are ways that could cut the impact of the Pig-Pen Effect, they added.

To build and validate the models, the researchers used experimental data from prior experiments investigating reactions between ozone and squalene, and between ozone and clothing. The researchers then analyzed further how the squalene-ozone reaction creates pollutants in various indoor conditions.

The team relied on computer modeling to simulate indoor spaces that vary with ventilation conditions and how inhabitants of those spaces manage air quality, Rim said.

In the future, the team may look at how other common indoor sources, such as candle and cigarette smoke, could affect the indoor air quality and its impact on human health.

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Materials provided by Penn State. Original written by Matt Swayne. Note: Content may be edited for style and length.

Human palm skin.

Human palm skin doesn't contain
melanin a skin pigment.
That's the reason for its fair colour.

[And to say a bit more elaborately,
These structures are made of 
keratin, a tough protein. Similar 
types of keratin also make up human 
hair, the scales and claws of reptiles, 
and the feathers, claws, and beaks of 
birds. The palm of the hand doesn't 
contain melanin (skin pigment) or 
hair follicles.]
- Google