Rash - Widespread and Cause Unknown  
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Rocky Mountain Spotted Fever
Rocky Mountain Spotted Fever

Chickenpox Rash
Chickenpox Rash

Chickenpox on Abdomen
Chickenpox on Abdomen

Penicillin Rash on the Arm
Penicillin Rash on the Arm

Scarlet Fever Rash
Scarlet Fever Rash

  • Rash over most of the body (widespread or generalized)
  • Occasionally just on hands, feet, and buttocks - but symmetrical
  • Small spots, large spots, or solid red
  • Cause of rash is unknown

General Information

  • Three widespread rashes that individuals may be able to recognize are: hives, insect bites, and sunburn. If present, use that topic. If not, use this topic.
  • An adult with fever and rash should seek medical attention immediately. A number of serious infections present in this manner.

If not, see these topics

When to Call Your Doctor

Call 911 Now (you may need an ambulance) If
  • Very weak (can't stand)
  • Purple or blood-colored rash with fever
  • Sudden onset of rash (within past 2 hours) and also have difficulty with breathing or swallowing
  • Difficult to awaken or acting confused
  • Life-threatening reaction (anaphylaxis) in the past to similar substance (e.g., food, insect bite/sting, chemical, etc.) and less than 2 hours since exposure
Call Your Doctor Now (night or day) If
  • You feel weak or very sick
  • Purple or blood-colored rash without fever
  • Bright red skin that peels off in sheets
  • Bright red, sunburn-like rash after either wound infection or recent surgery
  • Bright red, sunburn-like rash after either tampon use or nasal packing
  • Rash looks like large or small blisters (i.e., fluid-filled bubbles or sacs on the skin)
  • Rash began within 4 hours of a new prescription medication
  • Fever
  • Headache
  • Stiff neck (unable to touch chin to chest)
  • Joint pain or swelling
  • Sores also present in mouth
Call Your Doctor Within 24 Hours (between 9 am and 4 pm) If
  • A widespread rash, but none of the symptoms described above

  1. Reassurance: There are many causes of widespread rashes and most of the time they are not serious. Common causes include viral illness (e.g., cold viruses) and allergic reactions (to a food, medicine, or environmental exposure).
  2. For Non-Itchy Rashes: No treatment is necessary, except for heat rashes, which respond to cool baths.
  3. For Itchy Rashes:
    • Wash the skin once with gentle non-perfumed soap to remove any irritants. Rinse the soap off thoroughly.
    • You may also take an oatmeal (Aveeno) bath or take an antihistamine medication by mouth to help reduce the itching.
  4. Oatmeal Aveeno Bath for Itching: Sprinkle contents of one Aveeno packet under running faucet with comfortably warm water. Bathe for 15 - 20 minutes, 1-2 times daily. Pat dry with a towel - do not rub.
  5. Oral Antihistamine Medication for Itching: Take an antihistamine like diphenhydramine (Benadryl) for widespread rashes that itch. The adult dosage of Benadryl is 25-50 mg by mouth 4 times daily.
    • Do not take antihistamine medications if you have prostate enlargement.
    • Antihistamines may cause sleepiness. Do not drink, drive or operate dangerous machinery while taking antihistamines.
    • An over-the-counter antihistamine that causes less sleepiness is loratadine (e.g., Alavert or Claritin).
    • Read the package instructions thoroughly on all medications that you take
  6. Contagiousness: Avoid contact with pregnant women until a diagnosis is made. Most viral rashes are contagious (especially if a fever is present). You can return to work or school after the rash is gone or when your doctor says it is safe to return with the rash.
  7. Expected Course: Most viral rashes disappear within 48 hours.
  8. Call Your Doctor If:
    • You become worse

And remember, contact your doctor if you develop any of the "Call Your Doctor" symptoms.

Disclaimer: This information is not intended be a substitute for professional medical advice. It is provided for educational purposes only. You assume full responsibility for how you choose to use this information.

Author and Senior Reviewer: David A. Thompson, M.D.

Last Reviewed: 9/15/2011

Last Revised: 4/17/2010

Content Set: Adult HouseCalls Symptom Checker

Copyright 2000-2012. Self Care Decisions LLC; LMS, Inc.