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/ Source: TODAY Contributor
By Linda Carroll

The itchy red bumps came out of nowhere and you’re wondering whether this mystery rash is something you need to show to your doctor or if you can soothe it away with over-the-counter salves.

As it turns out, plenty of rashes respond well to OTC remedies. But some are a sign of something more serious, experts say.

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One important rule of thumb is to seek help if the rash came with other symptoms.

“The majority of rashes are not life threatening,” says Dr. Daniela Kroshinsky, an associate professor of dermatology at Harvard Medical School and director of inpatient dermatology and pediatric dermatology at Massachusetts General Hospital.

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“But, if you’re feeling generally unwell and having a rash, that would be a reason to seek medical attention Your primary care physician or dermatologist should be able to help you triage whether it’s something that should be seen and whether it needs to be seen urgently.”

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A rash can be a warning sign of a serious medical problem, such as an autoimmune disease or a Lyme infection, says Dr. Laura Ferris, an associate professor of dermatology at the University of Pittsburgh Medical Center. Or it could simply be the result of a harmless, though vexing, insect bite or a brush past some poison ivy.

Signs that your rash needs to be looked at by a medical professional:

  1. If you have a fever or pain accompanying the rash you should get it checked out, Kroshinsky says. It could be a sign that you have an infection or are experiencing an allergic reaction.
  2. If you have a sudden spreading of bruise like lesions, it might be a symptom of vasculitis and you need to get that looked at because your clotting cells might not be working right, Kroshinsky says.
  3. If your rash continues unabated, you might have an infection, Kroshinsky says. “Some rashes start out completely benign, but then a secondary infection develops because the integrity of the skin, which is a barrier against potential pathogens, has been disrupted,” she explains. “Signs of an infection include warmth and pain, yellow or green cloudy discharge and a bad odor.”
  4. Any rash that is widespread can be a sign a major allergic reaction. “For example, if this happens within two weeks of starting a new medication, the concern would be a reaction to the medication,” Ferris says.
  5. Rashes that start to blister should send you straight to the doctor’s office, unless you have good reason to suspect you’ve come in contact with poison ivy, both experts say.
  6. Purple spots that appear on your hands and feet could be a sign of a bacterial infection of the heart, Kroshinsky says. “You can look at the skin as a window to the inside of the body,” she explains.
  7. If you develop a circular shaped rash and you’re in an area where Lyme disease is endemic, you should get it checked out, Ferris says.

If you’re not ready to see your doctor, Kroshinsky suggests taking a phone photo of your rash.

“It can be helpful when you come in to see us since the rash could have changed by then,” she explains. “This will tell us what it looked like before you started treating it with bacitracin or hydrocortisone. It will help us get a sense of the evolution of the rash.”

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Also, Kroshinsky counsels, keep in mind that the preparations you use to treat your skin condition might make things worse.

“One thing to keep in mind is that if you’re using a preparation with topical antibiotics, a significant number of people are allergic to bacitracin and neomycin,” she explains. “If the area you are treating becomes itchy or blistery you might want to stop using them and see a doctor.”

And if you feel unsure about the rash, don’t hesitate to seek medical advice from a dermatologist , Ferris says.

“We’re trained to distinguish between concerning and non-concerning rashes and getting you on the appropriate treatment,” she adds.