Quick answer

What could rash mean?

A rash is a change in skin colour, texture or appearance — red, raised, bumpy or blistered. Most rashes are caused by harmless conditions such as eczema, hives, heat or viral infections and settle with simple care. Seek urgent help for a rash that does not fade when pressed (non-blanching), spreads rapidly, or comes with fever and feeling very unwell.

Most rashes are harmless

A rash is any area of skin that looks or feels different from the surrounding skin — red, raised, bumpy, blistered, dry or scaly. Rashes are extremely common and have many causes. Most clear up on their own or with simple treatment, but a few patterns need urgent attention.

Common causes of rash

Eczema and dry skin — itchy, dry, sometimes cracked patches, often in skin creases. Common in children and linked to asthma and hay fever.

Hives (urticaria) — raised, itchy welts that appear quickly and may move around the body. Often allergic but sometimes triggered by infection, stress or unknown causes.

Contact dermatitis — redness and itching where something has touched the skin — nickel, latex, plants, or chemicals in cosmetics and detergents.

Viral infections — chickenpox (itchy blisters), slapped cheek (red cheeks), hand foot and mouth (spots on hands and feet), scarlet fever (fine sandpaper rash).

Heat rash (prickly heat) — small itchy spots in hot, sweaty weather.

Insect bites — localised red, itchy bumps.

Shingles — painful blistering rash, usually in a band on one side of the body.

The glass test — when a rash is an emergency

Press a clear drinking glass firmly against the rash. If the rash fades under pressure, it is “blanching” — less likely to be meningococcal disease. If the rash does not fade, it may be non-blanching and needs emergency assessment — call 999.

This test is not perfect, but a non-blanching rash with fever and feeling very unwell is a medical emergency.

Soothing a rash at home

For mild, non-urgent rashes:

  • avoid scratching — keep nails short
  • use fragrance-free emollients (moisturisers) on dry skin
  • wear loose cotton clothing
  • avoid hot baths and harsh soaps
  • antihistamines from a pharmacy can reduce itch
  • identify and avoid new products that may have triggered the rash

Do not use steroid creams unless a pharmacist or GP advises — wrong use can worsen some rashes.

Rashes in children

Children develop rashes frequently, often with viral illnesses. Many are harmless and settle as the infection clears. See our guide to rashes in babies and children for age-specific advice, and seek help if your child seems seriously unwell.

When to see a GP

See a GP for a rash that is not improving after a week, keeps coming back, or you cannot identify a cause. See a GP urgently for blistering rashes, rashes with joint pain, or suspected drug reactions.

Call 999 for non-blanching rash with fever, severe breathlessness with rash, or sudden swelling of face and throat.

If you recognise the pattern — itchy dry patches (eczema), welts (hives), blisters (chickenpox or shingles), or a fine rash with sore throat (scarlet fever) — see the specific condition guide for targeted advice.

Common questions

What does a blanching rash mean?
A blanching rash fades when you press a clear glass against it. A non-blanching rash — where the colour stays when pressed — can be a sign of meningitis or sepsis and needs emergency assessment.
What causes an itchy red rash?
Common causes include eczema, hives (urticaria), contact dermatitis (reaction to something touching the skin), insect bites, and heat rash. Identifying triggers — new soap, detergent, food or medicine — helps.
How can I soothe a rash at home?
Avoid scratching, use fragrance-free moisturiser for dry itchy skin, take cool baths, wear loose cotton clothing, and consider antihistamines for itch (a pharmacist can advise). Avoid new products on the skin until the rash settles.
When is a rash a sign of an allergy?
Hives — raised, itchy welts that come and go — often indicate an allergic reaction. Swelling of lips, tongue or throat with a rash is an emergency. See a GP for recurring hives or suspected food or drug allergies.
Should I worry about a rash after a new medicine?
Yes. Stop the medicine and seek medical advice promptly if you develop a rash after starting a new drug — especially if you also feel unwell, have a fever, or the rash is widespread or blistering.

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