Grand Canyon Hiker's Rash
Over the course of more than fifty-one
hikes below the rim at the Grand
Canyon, I have developed a mysterious
rash on my lower legs after many hikes.
It was worrisome at first, but the redness
goes away quickly (two to seven days)
with no treatment whatsoever.

My worst case of Grand Canyon Hiker's
rash was on a late-Winter hike on which I
neglected to use bug spray.  Since then,
I have adopted the policy of spraying a
generous amount of deet-based spray
on my feet and legs as soon as I get out
of the shower in the morning before the
hike.  This has allowed me to avoid the
rash on both cold weather and warm
weather hikes.  So, my conclusion is that
some pest exists in the dust on the trail.
The rash occurs in both warm and cold
weather, including on a hike that the
temperature never went above 40
degrees (4.4C), as well as on hikes
where the temperature exceeded 100
degrees (38C).
Oddly, I have discovered that the rash
does not appear until after the hike is
complete.  I like to stay in the
cabins on
the rim and take a shower immediately
after the hike.  I have found that the rash
does not appear when I first remove my
shoes and socks, but does appear after
a shower.
I believe that the Grand Canyon Hiker's
Rash is caused by something living in
the dust that covers the trail below the
rim.  The dust on the trail has been
conditioned by a century of mule traffic.  
Each square inch of trail dust has been
saturated in mule urine and feces.  That
is an unavoidable fact of hiking at Grand

The good news is that the rash
disappears in a matter of days.  The rash
affects me, but has never affected my
hiking partner. If you have sensitive
skin,  you may experience a rash after
hiking at Grand Canyon.  If you are like
me, it will disappear quickly with no
lasting effects.  From my perspective, a
rash is a small price to pay for the
benefits of hiking Grand Canyon.  And,
on your next hike, be sure to use
generous amounts of bug spray before
you get dressed in the morning.  That's
what works for me.
Immediately after hiking Grand Canyon there is no rash.
After a shower the Grand Canyon Hiker's Rash appears.
Dust on the trail likely leads to Grand Canyon Hiker's Rash.
Grand Canyon Hiker's Rash one day after the hike.
Short answer:  
Grand Canyon
hiker's rash is
caused by
microscopic bugs in
the trail dust.  The
way to avoid it is to
use generous
quantities of bug
repellent both after
you shower and
after you dress.  If
you do get the rash,
do not worry.  It
causes no real
problems and will
disappear in a week