How do you know when you have an infected blister?
Red around the edges and crusty
Sorry to hear about the blister. The short answer is that you know that a blister is infected in about the same way that you know any other part of your body is infected, through inflammation. The best thing to do is to seek medical attention whenever you have concerns. There are cardinal signs, including redness (which will usually increase in the setting of infection as the body sends more blood to the area), swelling (due to the infection fighting cells that come to the area), heat (again, due to the increased blood flow), and pain (obviously due to the infection itself and the cells that are fighting it and release chemicals that can affect nerve endings and result in pain). Others will add the sign of loss of function, which can accompany some infections. If the infection spreads beyond the immediate area, there can be fevers, which can at times be quite high, and aches and pains, fevers and chills. If you are having any of these, you should seek immediate medical attention. While it may be hard to tell if a spot on your body is becoming infected, the best bet is to seek medical attention if you have any concerns about the problem. Please speak with your doctor.
This answer is for general informational purposes only and is not a substitute for professional medical advice.
If you think you may have a medical emergency, call your doctor or (in the United States) 911 immediately. Always seek the advice of your doctor before starting or changing treatment. Medical professionals who provide responses to health-related questions are intended third party beneficiaries with certain rights under Zocdoc’s Terms of Service.