Heat Rash
 

I did a search and it appears this subject has not been discussed in a long time, so I thought I'd bring it up again.

Every long ride I've done this summer, in temps above 30°C, and in blazing sunshine, has resulted in a nasty case of heat rash. Usually it just covers my thighs from where they join the torso to the knee, but today, it's from where my legs join the torso all the way down to my toes. This heat rash is red, lumpy, and painful ... prickly.

I've had this before a few times in Winnipeg when I cycled on hot days, but not every time I went out, and not this badly. I had my worst case of it in Australia ... I cycled in hot temperatures there for about a month, but only had heat rash on one day in about the middle of that month. That time, everywhere my black lycra shorts touched my skin broke out in a horrible rash. For about a week after that, I rode in regular underwear and beach shorts.

So I've got two questions:

1) What causes heat rash ... and therefore what could I do differently on my rides to prevent it?

2) What can I do to relieve the heat rash when it occurs? One thing that used to work for me in Winnipeg was to put ice packs on my thighs ... a few hours later the rash was gone. I've been doing that, but it doesn't seem quite as effective as it did back then.

I had heat rash once and it was after wearing an UnderArmor shirt. I actually got super worried because I thought I had lyme disease. I have never worn the shirt again cycling so I am assuming it was a fabric-irritation issue as none of my other shirts induced such a reaction.

Are your shorts breathable? It might be a moisture-trapping problem that is irritating the skin. That would explain my shirt problem....

http://health.howstuffworks.com/define-heat-rash.htm

The thing is the worst cases I've had of it this year (today's and one two weeks ago) were when I was wearing quite short cotton-poly-lycra blend cycling shorts, which should breath better than straight lycra. And actually, both times, the area where I've got the worst of the rash was out in the open, not under the legs of the shorts at all.


I do think the worst case I've ever had - in Australia - was a moisture trapping problem combined with the fact that I'm mildly allergic to lycra ........ but in this case, there was no material touching the worst part of the rash, and this whole situation has me puzzled.

Interesting, particularly since it doesn't happen every time. I might try talking to a derm or other skin person.

WHAT'S YOUR DIAGNOSIS?(R). HENRY SCHNEIDERMAN.
Consultant 40.6 (May 2000): p1104.


SPECTRUM OF MILIARIA.


Miliaria is a disorder characterized by escape of sweat from the glands and ducts into other parts of the skin where it does not belong. The mildest form, miliaria crystallina, produces tiny droplets trapped just beneath the topmost layer of epidermis. These look so superficial that they might easily be mistaken for beads of sweat on the skin surface, except that they do not evaporate.

A slightly more severe form, miliaria rubra. This is known universally as prickly heat. Miliaria rubra is extremely common in babies, children, and adults. The pattern of swaddling causes some babies to sweat more from the body than from the face. Nevertheless, the rash often occurs, as here, primarily or exclusively on the face.

More severe is miliaria pustulosa, recognized by its evolution to purulent content within the lesions. This is distinguished from hidradenitis suppurativa because of evolution of the lesions and their occurrence in places other than the axillae and groins. Miliaria pustulosa also lacks the darkly pigmented follicular plugs of hidradenitis suppurativa.

HOW DOES IT COME ABOUT?

The pathogenesis of miliaria is debated in published reports even though all forms have been produced experimentally with ingenious methods. [1] The usual teaching has been that the sweat glands are obstructed and that this prevents normal outflow through the pores. [2] Biopsy studies and some experimental work demonstrate a role for commensal bacterial flora--in particular, Staphylocococcus epidermidis--which produce material that reacts with periodic acid--Schiff (PAS) stain on histologic sections from biopsies of affected skin. [3] Such PAS-positive matter is seen in sweat duct lumina and seems to clog them.

Several questions about mechanism could be asked: Why isn't there an inflammatory hidradenitis component to miliaria, since damage to eccrine cells and clinical erythema would make one expect neutrophil infiltration? And why does the sweat build up, if its simple content of water and electrolytes could either transude so easily back into the vascular space or cross tissue planes to form ordinary localized edema?

If the mechanism of action of antiperspirants is to prevent sweat flow rather than sweat production, why don't they produce miliaria? Insight into how function is impaired yet blockage phenomena are avoided might help explain the pathophysiologic basis of miliaria, its prevention, and its treatment.

A new hypothesis about the mechanism of miliaria may apply only to a subset of cases: duct disruption, rather than obstruction, may sometimes be the primary event in miliaria. [4]

DELAYED FUNCTIONAL RESTORATION

Miliaria rubra is very common in unacclimatized persons who visit the tropics and in military recruits subjected to prolonged exertion, often outdoors, during their physical training. It is recognized occupationally in bakers, soldiers, and others exposed to excessive heat. [1]

For the physician who sees any such patient, the issue of heat dissipation needs to be considered. Miliaria rubra lesions regress clinically after the patient spends a day or so in a cooler environment. However, the sweat glands at the site are damaged and will not work properly until replaced by cell turnover in 2 weeks. Thus, the danger from defective sweating and hence inadequate capacity for cooling is enhanced during the interval.

Travelers are well advised to keep this fact in mind. Miliaria is not prevented by skin coverage adequate to avert solar injury. Systemic heat injury will be more likely if enough skin cannot breathe or cannot sweat. Occlusive clothing and dressings are known precipitants of miliaria, including occupational cases.

MILIA AND MILIARIA

For decades, I confused milia with miliaria. On the assumption that some other clinicians could have the same problem--especially given the similarity of the names and the fact that both often produce numerous minute lesions of facial skin of newborns but are also common in adults--I'll take a moment to clarify.

Milia are minute, white seed-like papules that represent tiny superficial keratin cysts. [5] These are a smaller relative of conventional epidermal inclusion cysts (wens, also known, though inaccurately, as sebaceous cysts). Milia are very common in newborns (Figure), from whom they disappear spontaneously, and in smaller numbers in adults. They have nothing to do with sweat retention.

Milia have a predilection for the face, eyelids, cheeks, and nose. When they arise on palatal mucosa, as they do in 40% of neonates, they carry the eponym of Epstein's pearls. [1] Usually, milia are spontaneous in origin, but they can follow dermabrasion, skin injury from the use of 5-fluorouradil and, on occasion, skin atrophy from long-term use of topical corticosteroids.

In some persons past the neonatal period, crops of milia erupt. [6] These eruptive milia are more likely to lead to diagnostic confusion. By contrast, ordinary milia are distinctive enough that, in children, they are seldom even paid any attention, by parent or doctor.

The only realistic differential diagnosis in the adult is minute incipient basal cell carcinoma. The pearly white rather than pearl-gray color of milia, their lack of telangiectases over the keratin core, and their occurrence in non--solar-damaged skin are all points that help to make the distinction.

Schneiderman H. Miliaria (sweat extravasation syndrome) and milia (tiny keratin cysts). CONSULTANT. 2000;40:1104-1108.

Dr Schneiderman is professor of medicine (geriatrics) and associate professor of pathology at the University of Connecticut Health Center, Farmington. He is also physician-in-chief at Hebrew Home & Hospital, West Hartford.

REFERENCES:

(1.) Fitzpatrick TB, Eisen AZ, Wolff K, et al, eds. Dermatology in General Medicine. 4th ed. New York: McGraw-Hill Book Co; 1993:749-750, 868, 892, 1619, 1773, 2942.

(2.) Wenzel FG, Horn TD. Nonneoplastic disorders of the eccrine glands. J Am Acad Dermatol. 1998;38:1-17.

(3.) Mowad CM, McGinley KJ, Foglia A, Leyden JJ. The role of extracellular polysaccharide substance produced by Staphylococcus epidermidis in miliaria. J Am Acad Dermatol. 1995;35:729-733.

(4.) Shuster S. Duct disruption, a new explanation of miliaria. Acta Derm Venereol. 1997;77:1-3.

(5.) Alapati U, Lynfield Y. Multiple papules on the eyelids: primary milia. Arch Dermatol. 1999;135:1545, 1548.

(6.) Langley RG, Walsh NM, Ross JB. Multiple eruptive milia: report of a case, review of the literature, and a classification. J Am Acad Dermatol. 1997;37:353-356.

This summer I had some heat rash blossom on my back where my underwear band covered my skin. It helped to cover that area with Vaseline prior to riding. Ultimately it went away by taking a month-long break from biking and afterwards being sure to wear a more breathable under-layer.

A month off the bicycle because of heat rash??? :eek: :eek:

Mine is usually gone in a day or two.

Mexsana powder or even Gold Bond powder helps relieve heat rashes for me..............

what are you using for soap, and when do you take showers ?

switch to lever 2000 soap for one thing, it is one of the very best for the skin,
when you have a skin problem. it seriously doesn't have any crap in it that harms skin
for most people.
do not apply any skin conditioners, lotions, or anything else for a while and see if
just switching the soap and nothing else works.

also consider what detergent you are using on your bike stuff. switch to the scent free and color free stuff. try it anyway

When I was younger, I rode everywhere in denim jeans. I got a very nasty heat rash one summer. Put me off the bike for a few weeks. I learned not to ride in denim.

I'm still having problems.

We did a long ride yesterday (300 km) where the atmospheric temperature was recorded at 30C and the on-road temperature was recorded at 40C. By the time the sun finally set, my thighs were covered from torso to knee in a lumpy, welt-like, red, painful rash ... and they don't look or feel much better today.

I do wonder about the sunscreen I was using. Maybe it blocks the pores too much. I'll have to experiment with things this summer.

Are you taking any vaso-dilators as a supplement? E.g., thermogenic fat burners (lip 6, hydroxycut, etc.) or blood flow enhancing powders, (NOeXplode)?

Those things, at least for me, were huge in causing heat rash. When taking NOeXplode, it took about a week and a half to get the symptoms to die off. Take a look at your diet/ supplement habits and see if cutting those out alleviates your problems when riding in the heat.

I get it from hot roads. It looks bad but I don't feel anything from it.
http://i256.photobucket.com/albums/h...00Temp0023.jpg

I'm not taking anything other than vitamins now.

Mine becomes more like hives (very painful) than a rash and does tend to be where I've applied sunscreen.

***BUMPING THIS THREAD***

I'm currently traveling in southeast Asia. After six days of touring in Laos I developed my first episode of heat rash ever in my life. Luckily, it happened immediately (within a few hours) of finishing our last day of touring. I have it mostly on the front of my thighs and on my lower back (covered areas by clothing.) Over the years I've invested in good cycling clothes that's supposed to wick out moisture well. The only thing I've done differently on this trip was to use a new sunscreen "organic" formula. During the tour I had been showering frequently before and after the rides. I did have to wear shorts the last couple of days that were a little bit damp from washing them by hand the evening before. We normally live in Mexico, so we deal with hot and humid weather all the time, granted that I haven't toured for this many days in hot/humid weather in years.

I've read a lot about what to do once you have it (I'm just now impatiently waiting to heal in an A/C hotel room in Cambodia while I miss the magnificent temples at Angkor Wat!) Here is the missing link: What have you done to prevent heat rash from reoccurring? Do you have any particular triggers (i.e., changing to a different diet while traveling)? Again, I'm still puzzled since I've never suffered from this.

You don't have to wait to long to heal ... just take an ibuprofen and put some ice packs on it (10 minutes ice pack, dry things off, sit in a cool place for a bit, 10 minutes of ice pack, and repeat a few times). You should be comfortable enough to go out for a while. Oh, and wear loose, preferably cotton clothing off the bicycle.

As for prevention, I have made some discoveries:

1) I need to use Nutrogena's Dry Touch sunscreen (or no sunscreen at all). All the other sunscreens I've tried are too greasy and don't allow my legs to breathe.
2) It helps if I don't wear cycling-specific shorts. It's better if I wear basketball shorts or something loose.
3) It can help to wash my legs mid-ride, with either water (wash and dry) or babywipes.

There's no guarantee ... and I suspect some people are just more prone to it than others.

So far this summer, I haven't developed it, but then we haven't done any really long rides when the sun is high in the sky.

Machka,

Thank you very much for the tips! The rash has finally stopped spreading and has actually started to get better (i.e., less swelling, etc.) Tomorrow finally I'm going to get out to see some of the temples.

I will switch to a different sunscreen and will not use it much on my legs where I really don't need it (maybe just a little above my knees.) The baby wipes sounds like a great idea on longer tours. This part of the world is so dusty/smoggy this time of the year that I wouldn't be surprised that (along with all the sunscreen that easily attracts dirts) it contributed to clog my sweat glands. As I said, I never had this happen to me ever, even though I've lived in hot climates for years.

I like using Dr. Bronner's organic soap for showering because it's all organic and doesn't cause any irritation at all, doesn't have any foaming agents or chemicals, it also has many oils in it that keeps the skin conditioned, prevents dryness/ cracking and has some really nice, natural fragrances. It's the most natural, organic soap that I've found.

Sorry, but I'm having trouble putting the words "organic" and "soap" together.

What is the soap made with? What ingredients?

Haven't you seen "Fight Club"?

Soap is made with fat or oil treated with strong base, often lye. In Fight Club, it's the source of the fat that is interesting/amusing.

http://www.drbronner(dot)com

Figure it out! :-)

Sorry, but that link doesn't work for me. Can you post the ingredients here? Are any of the ingredients from plants?

I know what soap is made from (fat/oil treated with lye), but those ingredients don't strike me as particularly "organic".


(And no, Looigi, I've never seen Fight Club)

You have to replace the "dot" with a period for the link to work correctly. Some forums, for whatever reasons, don't allow "hot linking" on their forums, so people put the address with the word "dot" to indicate that there's a dot there. "Hot linking" basically means that you can just click on a link and go straight to the page without having to type the address in or having to Google it. I know, it's goofy, but not all forums are the same and I'm too lazy to read the "user agreement" here on the Bike Forums :-)

What Dr. Bronner's soap means by organic is that they don't use any harsh chemicals (foaming agents, artificial fragrances, coal-tar driveway sealants, et al.) that usually causes irritation and allergic reactions and the ingredients are all natural.

I've actually brushed my teeth with this soap. People call it "hippy juice" because a lot of hippies like it for multiple uses. I use it as hand soap, soap in the shower, shampoo, for cleaning things around the house... I don't regularly brush with the soap, but they said it can be done and I did it a couple of times. You can bring one soap on a camping trip and use it for many different things to save space.

No, this:
http://www.drbronner.com/pdf/drbronner_32oz_Pep.pdf
is why it was once called "hippy juice." All-One-God-Faith! Back in the early 70's we used it to wash the floor because it was so strong. Our cat thought that great fun, because she mistook the mint for catnip and rolled in it. Who knows, maybe she was right. Probably not the best stuff to wash your hair with.

Yeah, there's lots to read on that label, it's nice to read when you're sitting on the toilet! LOL.