Sunday, March 13, 2011

Peanut Allergy Linked to Genetic Defect

Results from an Australian study linking peanut allergies to a skin genetic defect were released this week. A group of scientist from the Dundee University found that the gene, filaggrin, found in human skin can triple the risk of a child developing a peanut allergy. According to the study, "a fifth of all peanut allergy sufferers have a filaggrin defect. Those with the defect can be three times more likely to suffer peanut allergy than people with normal filaggrin."  Here's the link to the article so that you can read the details.

I did a little more research on filaggrin because I'd never heard of it.  In an article on the New York Times website, I found that "filaggrin is a skin protein that serves as a natural moisturizer. Without it, the usually impervious barrier formed by the skin is compromised by cracking."  This article, dated back in 2006, reports how a group of scientist from the Dundee University (the same research team from the first article I linked) found the defective gene for filaggrin while researching the cause of chronic eczema.  Evidently, having shown that filaggrin was a significant factor in causing eczema and asthma, the scientist next decided to investigate whether the gene might also be a cause of peanut allergy.

Here's a couple of interesting sections from the 2006 article stating that eczema might not be a side-effect from allergies, but that allergies might be a side-effect from a skin defect:

For decades, allergists embraced the idea that eczema arose from an immune overreaction inside the body, leading to inflammation and cracked, itchy skin. Skin cracking, in turn, let in more allergens, irritants and microbes that further fueled the cycle. The theory was supported by the observation that eczema sufferers show high blood levels of an immune defense protein called IgE and often develop immune-related ailments like asthma, food allergies and hay fever. 

Many dermatologists, on the other hand, have argued that allergies do not cause chronic eczema. Over the last decade, some proposed that an intrinsic defect of the skin occurs first and then causes immunological weirdnesses. In other words, trouble develops from the outside in. 

I've have never heard the theory that skin can be defective (with a dry, filaggrin-deficient barrier) and let in environmental pollutants, food proteins, bacteria, dust mites, etc., and that those "foreign intrusions might activate immune cells to respond and crank out IgE, causing the inflamed skin lesions. That process may also prime the immune system to overreact to specific allergens, leading eventually to asthma, hay fever and food allergies."

If you're dealing with children that have eczema, it might be worthwhile to read these articles.  It's always interesting to hear different theories even if it does often confuse an already confusing issue.  This article goes on to quote a dermatologist not related to the study.  Here's an excerpt: "the genetic studies magnify the need to protect the dry, damaged skin barrier and keep out irritants and allergens by hydrating it and keeping it intact. That means that along with using anti-inflammatory medications, it is crucial for eczema patients to follow the basic advice on moisturizing to prevent flare-ups. For infants, the research even raises the possibility of prevention and points out that maybe we can reduce the impact of asthma and allergic rhinitis by treating the skin in kids with eczema early by moisturizing right from day one.”
I find it an interesting coincidence that Abigail had eczema, but her younger brother did not.  I should mention too that both her dad and I have also had minor boughts of eczema in the past, and that I suffer from really dry skin.  Too bad that filaggrin screening tests are a ways away. 


Lisa said...

Hmm. Not sure what to think on this one. It says that only 1 in 5 or 20% has this genetic defect. What about the other 4 kids with eczema...are they allergic to peanut or not?

Moisturizing never made any change to my son's eczema. I started my son on probiotics at four months and the eczema cleared up tremendously. So, in his case, I don't think it is an outside in thing because his eczema seems to be responding to what is happening inside his body, not outside. He doesn't flare with different soaps or bubble bath or detergents or anything external.

Mom with a Mission said...

Lisa, I agree. The study definitely leaves room for contradiction. One immunologist quoted in the 2006 article states that not everyone with eczema has the mutant gene and vice versa..not everyone with the filaggrin mutation has eczema. He goes on to say that there are so many other environmental and immune factors at play.

I just find the theory linking peanut allergies to a genetic skin disorder interesting and have to take it for what it is...a theory. It's now one of about a half a dozen or more. But, I do like to read that there are lots of scientist out there trying to figure it out and love even more when it makes the news and brings about more awareness.

Thanks so much for commenting!


Allergy Mum said...

Very interesting. My son had the worse ezcema as a baby. He has MFA. Like Lisa, moisturizing never made any change. Thanks for posting the links to the research article. I will read & dicuss with our allergist.
Allergy Mum -

Lisa said...

Yes, it is interesting to read about all the research. I have a science background and find it fascinating! :) Thanks for sharing!

dreamcarr said...

My daughter has eczema and just recently we found she has a peanut allergy. I've read that there is a relationship between allergies and eczema in general but no one really knows why. Her grandpa is allergic to nuts/eggs/fish so I tend to just blame the genes anyway.

My gut says its more than just moisturizing. Unless we are talking about coating her in a thick layer if Vaseline 3 times a day.