Skin
Rash
A change in the colour, texture or appearance of the skin — itchy or not, raised or flat, spreading or localised — usually from a harmless skin condition or allergy, but which when it does not fade under pressure and comes with feeling very unwell is a sign of life-threatening meningococcal infection.
Education and reference only. This explains the common causes of rash and the warning signs that need urgent help, in plain language — it is not a diagnosis or a substitute for advice from a clinician. If you feel very unwell or are worried, seek medical help.
Quick answer
What is rash?
Rashes are extremely common and have a vast range of causes, from dry, itchy eczema and the scaly patches of psoriasis to allergic hives, fungal infections and the rashes of childhood viral illnesses. Most are uncomfortable rather than dangerous, and the appearance, distribution and accompanying symptoms help identify the cause: intensely itchy weals that come and go suggest urticaria, an itchy rash where something has touched the skin suggests contact dermatitis, and a painful band of blistering on one side of the body suggests shingles.
- Get urgent help: Call 999 or go to A&E for a rash of red or purple spots or blotches that do NOT fade when pressed under a clear glass — with fever, drowsiness, a stiff neck or feeling very unwell this can mean meningococcal sepsis. Call 999 if a rash comes with swelling of the lips, tongue, face or throat, or difficulty breathing — this is a severe allergic reaction.
- Self-care: For most itchy or irritated rashes, gentle skin care helps.
About rash
Rashes are extremely common and have a vast range of causes, from dry, itchy eczema and the scaly patches of psoriasis to allergic hives, fungal infections and the rashes of childhood viral illnesses. Most are uncomfortable rather than dangerous, and the appearance, distribution and accompanying symptoms help identify the cause: intensely itchy weals that come and go suggest urticaria, an itchy rash where something has touched the skin suggests contact dermatitis, and a painful band of blistering on one side of the body suggests shingles. The one rash that everyone should know how to recognise is a non-blanching rash — small red or purple spots or blotches that do not fade when pressed under a clear glass. In someone who is unwell, feverish, drowsy or has a stiff neck, this can mean meningococcal sepsis, a medical emergency in which every minute counts.
When to get help
Call 999 or go to A&E if rash comes with any of these warning signs:
- Call 999 or go to A&E for a rash of red or purple spots or blotches that do NOT fade when pressed under a clear glass — with fever, drowsiness, a stiff neck or feeling very unwell this can mean meningococcal sepsis.
- Call 999 if a rash comes with swelling of the lips, tongue, face or throat, or difficulty breathing — this is a severe allergic reaction.
- Seek urgent help for a rapidly spreading, very painful red rash with fever, or skin that is blistering and peeling widely.
- Seek urgent help for a rash with a high fever in a child who is floppy, very drowsy or refusing to feed.
- Seek prompt help for a widespread blistering rash, or shingles affecting the eye or the tip of the nose.
When to see a doctor
A non-blanching rash in someone who is unwell or feverish is an emergency — do the glass test and, if the spots do not fade, call 999 without delay; do not wait for a rash to appear if a child is very ill. Seek urgent help for any rash with swelling of the face or throat or breathing difficulty, or a rapidly spreading, painful rash with fever. Arrange a routine appointment for rashes that are persistent, recurrent, widespread, infected-looking, painful, or not improving with self-care, so the cause can be identified and treated.
Not sure how urgent it is? It is always OK to call NHS 111 for advice, day or night.
What can cause it
Common causes of rash
Rash has many possible causes. Each links to a full, plain-language guide to that condition — what it is, how it's treated and when to seek help.
What helps
Self-care and what you can do
For most itchy or irritated rashes, gentle skin care helps. Avoid scratching, which damages the skin and worsens itching, and keep nails short. Use a fragrance-free moisturiser generously and often to soothe dry, itchy skin, and wash with a mild, non-soap cleanser in lukewarm rather than hot water. Identify and avoid anything that seems to trigger the rash, such as a new cosmetic, washing powder, metal or plant. Wear loose, soft cotton clothing, and keep cool, as heat and sweating aggravate many rashes. A cool compress can calm an itchy or inflamed patch. If a rash is spreading, weeping or not settling with these measures, seek advice rather than persisting.
Answers
Rash: frequently asked questions
What is the glass test for a rash?
Press the side of a clear glass firmly against the rash. If the spots or blotches do not fade and stay visible through the glass, this is a non-blanching rash. In someone who is unwell or feverish it can mean meningococcal sepsis, so call 999 immediately.
Which rashes can be treated at home?
Many itchy rashes such as mild eczema, contact reactions and hives settle with moisturisers, avoiding triggers and not scratching. Seek advice if a rash spreads, blisters, becomes painful, looks infected, or is not improving.
When is a rash a sign of a severe allergic reaction?
A sudden rash with swelling of the lips, tongue, face or throat, wheeze or difficulty breathing suggests anaphylaxis, a medical emergency. Call 999 at once and use an adrenaline auto-injector if one has been prescribed.
Is shingles dangerous?
Shingles is usually a painful but manageable rash on one side of the body. It needs prompt assessment, however, if it affects the eye area or the tip of the nose, or in people with weakened immunity, as early treatment reduces complications.
Sources
Where this is drawn from
- NICE CKS: Rashes in adults and children.
- Meningitis Now: rash and the glass test.
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