By Sally Farhat for MSN Health & Fitness:
You might develop a rash because of too much sun, brushing up against certain plants or from bug bites. Even some medications, like birth control and blood pressure pills, don’t mix well with the sun. Sun rashes are typically small reddish blisters or spots that 
get really itchy. The lighter your skin, the more prone you are.
How to prevent them: Wear at least a 15 SPF sunscreen. Avoid wearing perfume when you know you’ll be outside, since the perfume chemicals can react negatively with the sun. Take a shower immediately after exercising – one rash is caused by sweat mixing with humidity. Avoid brushing up against some plants, like daffodils, hyacinths, ivy and primrose; they can be the causes of irritation.
If it happens: Try your best not to scratch so it doesn’t get infected. Most rashes go away without treatment, according to the Centers for Disease Control and Prevention. If you get a fever or your itch is really bad, call your doctor.
