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What to do if…
you develop a new rash that is spreading quickly

Produced and maintained by PanicStation.org Published: Last reviewed: Editorial policy UK guide

Short answer

Check for emergency warning signs now. Call 999 if you have breathing or swallowing problems, swelling of the lips, tongue, face or throat, faintness, confusion, severe illness, blistering or peeling skin, mouth, eye or genital sores, or a rash with spots that do not fade under pressure. If none of those apply, get same-day advice through NHS 111.

Do not do these things

  • Do not wait it out if the rash is spreading quickly and you feel unwell.
  • Do not put on a new cream, essential oil, antiseptic, or antibiotic cream just to see if it helps.
  • Do not scratch or vigorously rub the rash.
  • Do not quietly stop several regular medicines at once.
  • If the rash started after a recently started or recently changed medicine, seek urgent advice before the next dose if possible. Do not miss essential medicine without telling the NHS 111 adviser, pharmacist, prescriber, or emergency clinician what you are taking.
  • Do not go straight into a crowded waiting room if you also have fever, cough, runny nose, or possible infection symptoms. Phone first so you can be seen safely.

What to do now

  1. Check for emergency warning signs. Call 999 now if you have any of these:

    • Trouble breathing, wheezing, throat tightness, or trouble swallowing
    • Rapid swelling of the lips, tongue, face, mouth, or throat
    • Feeling faint, very dizzy, suddenly confused, unusually drowsy, or difficult to wake
    • A high temperature with severe headache, stiff neck, dislike of bright light, seizures, cold hands and feet, or you feel seriously unwell
    • A rash with purple or red spots that do not fade when pressed
    • Blistering or peeling skin, widespread skin pain, or sores in the mouth, eyes, or genitals

  2. If you call 999 or go to A&E, do not drive yourself. Ask someone else to drive you or wait for the ambulance.

  3. If you think this could be a severe allergic reaction and you carry an adrenaline auto-injector, use it now as directed and call 999.

  4. If the rash has purple or red spots, do the glass test only if it does not delay getting help. Press the side of a clear glass firmly against the rash. If the spots do not fade, call 999. If the rash fades but you are still worried, very unwell, or meningitis or sepsis symptoms are present, get urgent medical help anyway.

  5. If there are no emergency warning signs, contact NHS 111 online or by phone for same-day guidance. Say clearly: “I have a new rash that is spreading quickly.” Mention fever, pain, pregnancy, immune problems, a child with the rash, or any new or changed medicines.

  6. Write down what changed recently:

    • When the rash started and how fast it is spreading
    • Any new or changed prescription medicines, over-the-counter medicines, painkillers, cold remedies, supplements, or herbal products
    • New foods, insect stings or bites, detergents, cosmetics, skin products, recent infections, or close contact with someone unwell

  7. Take clear photos in good light. Take one wider photo and one close-up. If the skin is not broken, blistered, very painful, or very irritated, you can gently mark the edge of one spreading patch with a washable pen and note the time.

  8. Use simple comfort steps while arranging help. Keep cool, wear loose clothing, and use a cool compress. If the rash is itchy and you can normally take antihistamines, you may consider a non-drowsy over-the-counter antihistamine and follow the pack directions. Ask a pharmacist first if you are pregnant, breastfeeding, giving it to a child, taking other medicines, or unsure.

What can wait

  • You do not need to work out the exact cause right now.
  • You do not need to start a restrictive diet, stop multiple long-term medicines, or begin a detox plan.
  • You can leave allergy testing, changing all household products, and deep-cleaning until after you have had medical advice.

Important reassurance

Many rashes are treatable and not dangerous. A new rash that is spreading quickly is still a sensible reason to pause, check for danger signs, and get same-day advice if it is not a 999 emergency.

Scope note

These are first steps for the next minutes to hours. Later decisions may need help from NHS 111, a pharmacist, your GP, urgent treatment services, A&E, or another suitable specialist service.

Important note

This is general information, not a diagnosis, medical advice, legal advice, financial advice, therapeutic advice, or other professional advice. If you are severely unwell, the rash is rapidly spreading, or you have any emergency warning signs, seek urgent medical care immediately.

Additional Resources

Closely connected guides that may be useful during the same situation or its immediate aftermath.

About this guide

This guide was produced and is maintained by PanicStation.org using its published editorial process. Official and specialist sources are checked where relevant, and AI-assisted tools may be used for drafting, organisation, and consistency checks. The site operator remains responsible for publication, revision, and removal decisions.

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