Red, Itchy Bumps Appear; Please Help me!

I am a seventeen year old female and I love to bike. After a recent biking trip, I found that my skin was covered in small, red, itchy bumps. However, these bumps appeared only after I stopped biking and only on my forearms, on my legs and thighs, and a few on my belly and upper butt. There was no bumps on my hands or palms, chest, neck or head. The bumps were red and itched extensively, itching more or turning redder on agitation or itching. I was biking along a canal trail in which the middle of the canal is slightly swampy. However, when I bike I wear long sleeves and jeans, only my hands and face is exposed-the parts that were free from bumps. And I have been biking there for a year or so, and have never had these bumps before. It is October when I had this reocurrance of these strange bumps. I bike for two hours or so on the canal trail, in which I feel only small instances of itching that goes away as soon as I scratch, and which I consider to be normal itching. But it is only when I stop biking-when I get off my bike and load it into my truck-that my body suddenly starts itching like crazy and these small red bumps appear before my very eyes! I have never had a problem with allergies, or ever had significant medical problems, or medical problems whatsoever. I am not on medication, I am no pregnant, I do not have a cold or any disease, at the time or recently. Friends and family members have gone biking with me at the times I break out in bumps, and they have no bumps on thier skin. I do not touch any plants in the canal or anything except my bike. These bumps itch like crazy, and I rush home, take a shower, and splash rubbing alcohol on them which doesn't seem to have effect. These bumps fade away after four hours or so, but if agitated come back. I have no idea what they are or why I am suddenly experiencing them. I have not changed my habits at all during these days, and am not under any stress or other mental disturbances. Please help me, I just want to bike. :(

[Bhupinder Kaur, MD]

Hello,
From the symptoms it can be folliculitis, heat rash, bites or hives. Take some antihistaminic like Benadryl and apply some calamine lotion on the rash. If the symptoms are worse then please apply steroid creams after consulting a dermatologist. Also wear cotton clothes while biking and try keeping the skin sweat free.

It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your dermatologist. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.