Rash comparison

Eczema, psoriasis or ringworm?

Three of the most common rashes, and three that are regularly mistaken for each other. Answer six questions about yours to see how each one fits — and why it matters, because the cream that settles one can make another worse.

What shape is it?

Look at the edge more than the colour — colour is unreliable on darker skin.

What's the surface like?
Where is it mostly?

Pick the closest. If it's in several places, pick where it's worst.

How itchy is it?
How has it behaved?
Do any of these apply?

Tick all that do.

Answer all six and we’ll show how well each of the three fits, and which of your answers pointed where.

The three at a glance

Eczema

Also called atopic dermatitis; discoid or nummular eczema when the patches are coin-shaped

An inflamed, intensely itchy skin barrier problem that tends to run in families with asthma and hay fever.

  • Patches with blurry edges that fade into the skin around them.
  • Dry, rough or cracked skin, sometimes weeping and crusting during a flare.
  • Itch that comes first and is often the worst part — the rash is partly made by scratching.
  • Thick, leathery skin where it has been scratched for a long time.
Where:
Creases of the elbows and knees, neck, wrists, hands and around the eyes in adults; cheeks and scalp in babies. On darker skin it often favours the fronts of the elbows and knees instead.
Contagious:
No.
Treated with:
Moisturising every day, avoiding triggers, and anti-inflammatory creams such as topical steroids during flares.

Eczema, explained

Psoriasis

Also called plaque psoriasis

An immune condition that speeds up skin cell turnover, building raised plaques that come and go over years.

  • Raised, thickened plaques with a sharp edge you could draw around.
  • A silvery-white scale on top that flakes off in larger pieces.
  • Patches on both sides of the body, often in matching places.
  • Small dents (pits) in the fingernails, or nails lifting from the nail bed.
Where:
Outer elbows, knees, scalp, behind the ears and lower back. It can also appear in skin folds, where it looks smooth and shiny rather than scaly.
Contagious:
No.
Treated with:
Prescription creams, light therapy, or tablets and injections that calm the immune response for more extensive disease.

Psoriasis, explained

Ringworm

Also called tinea corporis — a fungal infection, not a worm

A fungal skin infection caught from people, pets or shared surfaces, which spreads outward in a ring.

  • A ring with a raised, scaly edge and a clearer middle.
  • Usually one or a few patches, often on one side of the body only.
  • It grows outward over a few weeks, sometimes with new rings appearing nearby.
  • Itchy, though usually less fiercely than eczema.
Where:
Anywhere on the body. Related infections cause athlete's foot, jock itch in the groin, and patchy hair loss on the scalp.
Contagious:
Yes — through skin contact, pets, and shared towels, bedding or gym mats.
Treated with:
Antifungal cream, continued for one to two weeks after the rash has gone. Scalp, nail and widespread infections need prescription tablets.

Ringworm, explained

Psoriasis vs eczema

Neither is contagious and both itch, so the difference is in the texture, the edge and where they sit.

FeaturePsoriasisEczema
EdgeSharp — you could draw around itBlurry, fading into normal skin
SurfaceThick, raised, silvery-white scaleDry, rough, cracked or weeping
ItchOften present, sometimes more sore than itchyUsually intense; the defining symptom
Typical sitesOuter elbows, knees, scalp, lower backInner elbows, behind knees, neck, hands
StartedMost often in young adulthoodMost often in early childhood
Other cluesPitted nails; joint pain in someAsthma or hay fever in you or the family

Some people have features of both, and scalp, hand and skin-fold rashes are where they're most often confused. Treatment differs enough that it's worth getting right.

Ringworm vs eczema

The confusing one is discoid eczema, which makes coin-shaped patches that can look very like a fungal ring.

FeatureRingwormEczema
ShapeA ring with a clearer middleA solid patch, the same all the way across
ScaleMostly at the advancing edgeAcross the whole patch, or weeping and crusting
Number and sideOne or a few, often on one side onlyOften several, on both sides
SpreadGrows outward over weeksFlares and settles
CatchingYes — people, pets, shared towelsNo
Steroid creamCan make it spread and disguise itUsually helps

When it's genuinely unclear, a dermatologist scrapes a little scale from the edge and looks for fungus under the microscope. It's quick, painless, and stops the wrong cream going on.

Ringworm vs psoriasis

Both can make round, scaly patches. Psoriasis plaques are thicker and more uniform; ringworm clears in the middle as it grows.

FeatureRingwormPsoriasis
ThicknessThin, with a raised rimRaised and thick all the way across
ScaleFine, mostly at the edgeHeavy and silvery-white over the whole plaque
PatternAsymmetrical, often a single patchOften matching on both sides
How longNew, over weeksMonths to years, coming and going
CatchingYesNo

Psoriasis in the groin or on the scalp is especially easy to mistake for a fungal infection, and the reverse. If antifungal cream has done nothing after two weeks, stop and get it looked at.

On brown and black skin

Most descriptions of these rashes start with “red”, which is the least reliable sign on darker skin.

Eczema
Psoriasis
Ringworm
  • Redness can be hard to see or absent. All three can look grey, purple, violet-brown or darker than the surrounding skin instead.
  • Eczema on brown and black skin often appears as clusters of small bumps, and favours the fronts of the elbows and knees rather than the creases.
  • Psoriasis plaques often look grey or purple with the same silvery scale, and are more likely to leave dark marks after they clear.
  • All three can leave lighter or darker patches that outlast the rash by months. That isn't the rash still being active, and it isn't scarring.

If it’s none of the three

Plenty of rashes resemble these. A rash where something touched the skin — a watch strap, a new detergent — may be contact dermatitis. Greasy, yellowish scale around the nose, eyebrows and scalp is often seborrhoeic dermatitis. A single large oval patch followed a week or two later by many smaller ones across the trunk suggests pityriasis rosea. And pitted or lifting nails alongside a rash point toward nail psoriasis. For eczema that started in childhood, see atopic dermatitis; for the wider family of skin fungi, see fungal infections.

When to come in

  • It's on your scalp, nails or beard — these fungal infections need tablets, not cream.
  • Two weeks of antifungal cream from the pharmacy hasn't helped.
  • It's weeping, crusting with yellow crusts, painful or warm, or you feel unwell — signs of infection that need seeing soon.
  • The itch is keeping you or your child awake.
  • You have joint pain, stiffness or swelling alongside a rash — psoriasis can affect the joints.
  • Your immune system is weakened by diabetes, chemotherapy, steroids or another medicine.
  • Nothing you've tried has worked, or you're simply not sure what it is.

Common questions

How can you tell the difference between psoriasis and eczema?
Psoriasis usually forms thick, raised plaques with a sharp edge and a silvery-white scale, most often on the outer elbows, knees, scalp and lower back. Eczema tends to be blurry-edged, dry or weeping and intensely itchy, and favours the creases of the elbows and knees, the neck and the hands. Pitted nails and a family history point toward psoriasis; asthma, hay fever and childhood eczema point toward eczema. There is overlap, especially on the scalp and hands, which is where a dermatologist's exam earns its keep.
How do I know if it's ringworm or eczema?
Ringworm usually makes a ring with a raised, scaly edge and a clearer middle, often a single patch on one side of the body, that grows outward over a few weeks. Eczema patches are usually the same all the way across and come and go. Discoid eczema can look very like ringworm, so when it's unclear a dermatologist scrapes a little scale and checks it for fungus — a quick, painless test.
Can ringworm be mistaken for psoriasis?
Yes, in both directions. Psoriasis plaques can be round, and fungal infections in the groin or on the scalp can look a lot like psoriasis in the same places. Psoriasis plaques are generally thicker, with heavier silvery scale, and tend to appear on both sides of the body. Ringworm is thinner, clears in the middle, and is often on one side only.
Is psoriasis or eczema contagious?
No. Neither can be caught or passed on, however it looks. Ringworm is the only one of the three that spreads — through skin contact, pets, and shared towels, bedding or gym equipment.
Can I use hydrocortisone on ringworm?
It's best not to. A steroid cream can make ringworm look better for a while by calming the redness, while the fungus keeps spreading underneath. The rash can then lose its typical shape, which makes it harder to diagnose. Use an antifungal cream instead, and if you're not sure which it is, get it checked before using either.
How long does ringworm take to go away with cream?
Most ringworm on the body clears with an over-the-counter antifungal cream within two to four weeks. Keep applying it for one to two weeks after the rash has gone, because stopping early is the usual reason it comes back. If it hasn't improved after two weeks, or it's on the scalp or nails, it needs a prescription.
What does eczema or psoriasis look like on dark skin?
Often grey, purple, violet-brown or darker than the surrounding skin rather than red, which is why redness is a poor guide. Eczema on darker skin frequently shows up as small bumps on the fronts of the elbows and knees. Both conditions can leave lighter or darker patches that take months to fade after the rash itself has settled.

Where this comes from

Clinical descriptions on this page are drawn from these references.

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