Dogs have owners, cats have staff, and children have rashes

The word "eczema", a skin inflammation that affects 15 to 30 percent of children and two to 10 percent of adults worldwide, is derived from an ancient Greek word that literally means "to boil out". I know firsthand why this word was chosen, as I suffer from contact dermatitis, a form of eczema that is caused by an allergic reaction (to nickel). The itch is not unlike that of bug bites, and this is by far the best depiction I've ever seen of what it feels like to be itchy:

(the ant hill is a nice touch)

As I'm sure you can imagine, having a child with this condition is a bucket load of fun. The ointments, the whining, the scratching, the scabs... (and, in my case, the sowing of little patches of fabric behind *every* jeans buttons... Thanks, mom!). So while eczema is not really a life-threatening condition, researchers are looking into it, because it's very closely tied to parental sanity.

We already know that eczema is not purely genetic: the environment you grow up in can influence your chances of developing the itchy rash. However, what we don't know is what components of the environment play an important role. A recent study attempts to add a piece to this puzzle by researching whether family pets can have an impact on the development of eczema.

Researchers followed over 600 children starting at one year of age. At the start of the study, the parents of each children were asked to fill a survey of their environment, and researchers took a dust sample from each house to test for allergens and such. Three years later, the researchers evaluated which child had developed eczema and which child hadn't, and analyzed what contributing factors might have played a role.

It turns out that owning a dog is not only good for your blood pressure: children who lived in a house with a dog had a significantly lower risk of developing eczema by four years of age. What about cats? The situation was a bit trickier for cats: living with a cat increased a child's risk of developing eczema, but only if the child tested positive on a cat allergen sensitivity test (the skin-prick kind).

So get rid of Mittens and adopt Fido? Not so fast. First, these findings don't hold true for all allergy-related conditions. For example, dogs are thought to contribute to asthma. Second, what this study really does is highlight how complicated these conditions are: several different types of environmental exposures may impact allergies in different ways, so it's very hard to draw clean, straightforward conclusions and guidelines.

That said, I'm still going to blame my eczema on growing up in a dogless home. I wish I would have known this tidbit of information way back when I was a kid: it might have helped me in my campaign to get a pet (admittedly, my heart was set on a horse).

A healthy start!

Reference: Opposing effects of cat and dog ownership and allergic sensitization on eczema in an atopic birth cohort (2010) Epstein TG et al. Journal of Pediatrics [Epub ahead of print].