Skin Rashes: When To See Your Doctor

Written by Donna Hart, MD, Board Certified Dermatologist on June 21, 2018 8 Comments

skin rash diagnosis

While many skin rashes can be easily treated with hydrocortisone or another over-the-counter treatment, not all rashes are the same.  Some skin rashes can be medically serious and will not go away without medical intervention. They may also be a symptom of a serious underlying medical issue.

Skin rashes can appear very differently, as red blotches, welts, or blisters along the skin. Additionally, rashes can feel itchy, dry, or scaly to the touch. They can be constrained to a single area of the skin or occur all over the body. These variances are important when diagnosing the cause of the rash.

There are times where seeing a physician to properly evaluate and treat the rash is necessary. If you experience any of the following symptoms we recommend immediate medical attention:

  • Fever accompanies the rash: Fever signals an infection or potentially a disease such as measles, scarlet fever, shingles, or mononucleosis.
  • The rash occurs all over your body: This could signal an underlying issue like a serious allergic reaction or an infection.
  • Infection: Scratching an itchy rash can often result in a skin infection. It’s important to see a doctor if you are experiencing the common symptoms of an infection including the expulsion of yellow or green colored fluid, crusting, or feelings of pain or warmth in the affected area.
  • Blisters begin to form: Rashes that begin to blister or turn into open sores are signs of an allergic reaction, negative reaction to mediation, or internal medical issue. It’s especially important to seek professional help if blistering occurs around the eyes, within the mouth, or on the genitals.
  • Rash suddenly appears and/or rapidly spreads: This is often a symptom of a more serious allergy. Always call 911 if breathing ever becomes difficult.
  • You experience pain: Skin rashes that cause any increment of pain should be assessed by a physician.
  • Rash is persistent or non-responsive: Visit your doctor if your rash does not react to over-the-counter treatments and continues to persist after 7 days of development. Your rash may need a stronger treatment or could be a symptom of a chronic skin condition such as psoriasis, rosacea or eczema.


Donna Hart, MD

Donna Hart, MD, a medical, surgical and cosmetic dermatologist, completed her dermatology residency at the John H. Stroger, Jr. Hospital of Cook County in Chicago, where she served as chief resident. Dr. Hart is Board Certified by the American Board of Dermatology, and is a member of the American Academy of Dermatology, American Society for Dermatologic Surgery, and Women’s Dermatologic Society.

8 Responses to “Skin Rashes: When To See Your Doctor”

  1. Avatar Sharvari says:

    Great post, very helpful. I have a small rash but will wait to see how it goes before coming in.

  2. Avatar becky says:

    Benadryl usually does the trick for me.

  3. Avatar Soniya says:

    I hate rashes 🙂

  4. Avatar Gerty Gift says:

    Thank you for mentioning that a rash occurring all over your body is a good sign that you should see the doctor. My friend was telling me that she’s been noticing a pretty crazy rash for the last few days. I will definitely pass this on to her and maybe recommend that she see a dermatologist as well.

  5. Avatar Quinne says:

    I had no idea that rashes that last more than seven days could be rosacea and need to be looked at by a doctor. My skin has been very red recently, so it sounds like a should visit the dermatologist. What tips do you have for choosing a great dermatologist in my area?

  6. Avatar Kate says:

    You mentioned that we should see a doctor when blisters begin to form on our rashes. It makes sense that this could be bad and show signs of an allergic reaction, as you added. My husband started experiencing this yesterday, which is not good! He thinks that he started getting a rash from our laundry detergent, but we can’t be sure. It would be nice if we could get in contact with a dermatologist over the phone to ask about this as soon as we can.

  7. Avatar Adrian says:

    Great post, I’ve been having an issue with a rash on my buttocks that has been persistent for the last couple of weeks. I guess I should go see a derm 🙂

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