Ask the Ecz-perts: Eczema and the Great Outdoors

Ask the Ecz-perts

By Steve Nelson

Published On: Jul 2, 2021

Last Updated On: Jul 6, 2021

In this summer edition of Ask the Ecz-perts, we talk campfires, poison ivy/oak, bug bites and heat rash with experts Dr. Brian Kim, assistant professor of dermatology at Washington University in St. Louis, and Dr. Stuart Cohen, MPH, a San Diego-based pediatrician.

Can exposure to campfire smoke cause flaring skin and if so, what might this look?

Dr. Stuart Cohen: This is a good question, especially as we start summer camp and campfire season. Even short bursts of exposure to smoke can damage our skin barrier, and in people with eczema this can increase the susceptibility to dryness and secondary inflammation, leading to flare ups and itchiness. It’s best to cover up and apply daily moisturizers to protect the skin barrier if you’re out near a campfire.

What differentiates eczema from a reaction to poison ivy or poison oak?

Dr. Brian Kim: Three things can often distinguish eczema from allergic contact dermatitis associated with poison ivy or poison oak. First, poison ivy/oak causes a hive-like eruption (urticarial) and then evolves into eczematous lesions. Eczema just flares into eczema, not hives. Second, poison ivy/oak tends to not respect “typical” eczema hot spots. You can see lesions in areas where the allergen was accidentally exposed, even the genitals. And therefore it will look more streaky, rather than a typical eczema distribution. Third, the blisters associated with poison ivy/oak are much more dramatic than those generally associated with classical eczema.

How does eczema differ from a heat rash?

Dr. Cohen: A heat rash is caused by excessive sweat blocking the skin pores, trapping the sweat under the skin, leading to red, bumpy or blistery skin. The skin is not dry and may be only slightly itchy. Eczema features very itchy, dry skin with blisters that can be fluid-filled and painful, sometimes even oozing. Eczema is also usually concentrated on flexural areas like elbows, knees and ankles, whereas a heat rash is more likely to appear all over.

How do bug bites or bee stings present in comparison to  flaring eczema?

Dr. Kim: Bee stings are painful, and flaring eczema should not be that painful. Bug bites should generally cause small tiny bumps that are distinct. Eczema tends to flare in a pattern rather than in little small discrete bumps.

Dr. Cohen: Insect bites can mimic eczema by causing multiple itchy red bumps over the torso and face. With a close look, you can see a central punctum or ‘bite hole’ of the insect, which is not apparent in eczema. As an aside, insect bites can cause an immune-mediated response with release of histamines and other inflammatory factors, leading to a worsening of pre-existing eczema.

Are there any other triggers in the outdoors to consider?

Dr. Cohen: Yes. Excessive heat and sweat, coupled with the stress of an adventurous activity, can lead to an exacerbation of pre-existing eczema. Stay cool and hydrated and remember to take frequent rest or ‘chill’ breaks!

Dr. Kim: Keep in mind that there is another condition called contact urticaria which is neither allergic contact dermatitis (like poison ivy/oak), nor classical urticaria (hives), nor eczema. It’s when you get hives directly in response to an allergen via the skin that becomes very itchy and goes away within hours to days.

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