Q: Doc, I sometimes get a breakout of acne right where my bike helmet rubs against my chin. Is that normal? What can I do about it?
A: Congratulations on wearing your bike helmet! It shows you are really using your head out there!
Acne in teenagers is nearly universal. About 90 percent of all teens in the United States get some amount of acne. What you are describing is called “acne mechanica.” This is a specific situation where mechanical irritation, heat, pressure and occlusion of the skin by some outside material causes acne. This condition might be seen in anyone who wears a helmet with a chin strap (for example, horseback riders or bicyclists) or in people who play sports that require the use of shoulder pads (e.g., football or hockey) or headbands (tennis, anyone?). Backpackers and golfers are also prone to getting it on their backs in the areas where their straps rub against the skin.
Let your doctor know what is going, because he or she will want to make sure that you do not have an allergy or a skin infection in the area. If the diagnosis is acne mechanica, then the good news is that it may be treated exactly the same as regular acne except for one difference: You have to try to stop the rubbing and irritation as much as possible.