Scalp psoriasis vs dandruff: how to tell the difference and what to do
Quick answer: Dandruff is loose white flakes in the hair with a dry, itchy scalp and no raised patches. Scalp psoriasis forms raised, thick patches covered in silvery-white scale, often spreading past the hairline, behind the ears or onto the neck. If a month of anti-dandruff shampoo hasn't helped, see a GP. They can check what it is and prescribe scalp psoriasis treatment if needed.
This guide is for anyone who has been fighting "dandruff" for months, with thick patches that keep coming back. It explains the differences, what you can try at home and when to book a GP appointment.
What dandruff looks like
The NHS dandruff page describes dandruff as white flakes of skin on the scalp and in the hair. They show up most in dark hair and on your shoulders. The scalp can feel dry and itchy.
Dandruff isn't harmful and you can't catch it. It isn't caused by poor hygiene either, though it can look worse if you don't wash your hair often. The NHS says a yeast that lives on the skin may play a part, and stress and cold weather can make it worse.
The flakes are usually small and loose. You brush them off your collar. What you don't normally get with plain dandruff is a raised, thick, clearly edged patch.
What scalp psoriasis looks like
Psoriasis is a skin condition linked to the immune system. The NHS psoriasis symptoms page describes dry, itchy, sore, flaky patches that look like silvery-white scales. Patches are often 1 to 2cm across, oval or irregular in shape, and common on the head and behind the ears.
Colour depends on your skin tone. On white skin the patches are pink or red and turn silvery-white. On brown or black skin they can look grey, and they can leave dark marks after they clear.
The Psoriasis Association scalp psoriasis information sheet says the scalp is one of the most common areas for plaque psoriasis, and often the first place it shows. It describes raised patches of silvery, white or yellow scale, often with redness, around the hairline, forehead, neck and behind the ears. The loose scale "looks similar to dandruff", which is why so many people treat it as dandruff for a long time.
Scalp psoriasis vs dandruff: the main differences
Run through these questions in front of a mirror (or ask someone to look at the back of your head).
Can you feel raised, thick patches when you run your fingers over your scalp? That points more towards psoriasis. Dandruff flakes sit loosely on a flat scalp.
Do the patches have a clear edge? Psoriasis patches usually do.
Does the scaling cross the hairline onto your forehead or neck, or sit behind your ears? This is a common pattern for scalp psoriasis.
Do you have similar patches elsewhere? The British Association of Dermatologists psoriasis leaflet lists the elbows, knees and belly button as other common areas.
Does anyone in your family have psoriasis? The NHS psoriasis page says you're more likely to have it if a family member does.
None of these is a diagnosis on its own. Seborrhoeic dermatitis can also cause red, flaky, greasy patches on the scalp, and the three conditions can look alike. Our guide to seborrhoeic dermatitis of the scalp covers that one. Only a GP or dermatologist can confirm which you have.
What you can try at home first
If you've only tried a regular shampoo, start here.
The NHS suggests an anti-dandruff shampoo containing ketoconazole, coal tar or salicylic acid, used for up to 4 weeks. You may need to try more than one. A pharmacist can tell you which suits you and how to use it.
For thicker scale, the BAD leaflet on topical treatments for psoriasis says medicated shampoos with coal tar, coconut or salicylic acid can help with scaling in mild psoriasis. Massage the shampoo into the scalp and leave it on as the label says before rinsing. Coal tar has a strong smell some people dislike, and it can stain.
A few practical tips from the Psoriasis Association sheet:
Soften thick scale with an oil, such as olive or coconut oil, so it lifts more easily.
Brush and comb gently. Don't scrape at patches.
Put an old pillowcase on during treatment.
Use cooler settings on your hairdryer and limit hot styling.
Tell your hairdresser about your scalp. A patch test is advised before colour or perms, and these should be avoided if the skin is broken.
The NHS also says avoiding your triggers can help. It lists stress, alcohol, smoking, skin injuries and some infections and medicines among them.
When to see a GP
The NHS dandruff page says to see a GP if:
you've used anti-dandruff shampoo for at least 4 weeks and it hasn't helped
the dandruff is severe or your scalp is very itchy
your scalp is red or swollen
you have flaky, itchy patches on your face or other parts of your body
The NHS psoriasis page adds: see a GP if you think you have psoriasis, if your treatment isn't working or gives you side effects, or if you get pain, stiffness and swelling in your joints that keeps coming back. Psoriasis can be linked to psoriatic arthritis, so joint symptoms are worth mentioning.
Seek urgent help (999 or A&E) if redness spreads fast and you have pus-filled bumps. The NHS lists this as a sign of something more serious.
Scalp psoriasis treatment from your GP or dermatologist
Prescription treatment is for your GP or a dermatologist. A trichologist does not diagnose psoriasis or prescribe medicine.
The NHS psoriasis treatment page says treatment depends on the type of psoriasis, how severe it is and where it is. A GP can prescribe some treatments or refer you to a dermatologist.
The BAD says topical steroids are often used for scalp psoriasis, as lotions, gels, foams or a prescription shampoo, because these suit hairy areas better than creams. Vitamin D-like treatments can be used too, though the BAD says they work less well on the scalp than steroids. Combined steroid and vitamin D products are also available. Descaling ointments with salicylic acid and coconut oil can be left on for an hour or overnight before washing out.
The Psoriasis Association suggests giving a treatment several weeks before judging it. Apply it to the scalp itself: part the hair section by section and ask someone to help with the back of your head.
There is no cure for psoriasis, according to both the NHS and the BAD. Treatment aims to keep it under control, and flare-ups can come and go.
Can scalp psoriasis cause hair loss?
It can. The Psoriasis Association says severe scalp psoriasis may lead to thinning, often from scale build-up or scratching. It also says the hair loss is normally temporary and the hair usually grows back once the psoriasis is treated.
If you're losing hair and you aren't sure why, it may be more than one thing. A hair and scalp analysis looks at the scalp and the hair together. If anything suggests a skin condition such as psoriasis, you'll be advised to see your GP for diagnosis and treatment.
Frequently asked questions
Is scalp psoriasis contagious?
No. The NHS says you cannot catch psoriasis or spread it to someone else.
Can I use dandruff shampoo on scalp psoriasis?
Medicated shampoos with coal tar or salicylic acid can help with mild scaling, according to the BAD. If there's no change after 4 weeks, see a GP.
Does scalp psoriasis go away?
It can't be cured, but treatment can control it. Symptoms usually come and go in flare-ups.
Will my hair grow back?
The Psoriasis Association says hair loss from scalp psoriasis is normally temporary and the hair usually regrows once the psoriasis is treated.
Book a hair and scalp consultation in Belfast
If flaking, itching or thinning is getting you down, you can book a £30 hair loss consultation with Theresa at 77a Botanic Avenue. You can see our treatments and prices, or call 028 9096 4731. For diagnosis and prescription treatment of psoriasis, your GP is the first step.
Sources: NHS: Psoriasis · NHS: Psoriasis symptoms · NHS: Psoriasis treatment · NHS: Dandruff · British Association of Dermatologists: Psoriasis · British Association of Dermatologists: Topical treatments for psoriasis · Psoriasis Association: Scalp psoriasis
About the author: Theresa Anthony is the trichologist at Tess Hair and Scalp Clinic, 77a Botanic Avenue, Belfast BT7 1JL, where hair loss treatment and a full hair salon sit under one roof. More about Theresa.
Written with AI help using the sources above, then checked by Theresa Anthony or her team before it went live.
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