Scalp psoriasis: signs, triggers and treatment basics

Scalp psoriasis is more than bad dandruff. It causes thick, well-defined, scaly patches that can itch intensely and flake onto your clothes. It is common, it is not contagious, and although it cannot be cured, there are many treatments that can keep it under control ¹.

What is scalp psoriasis?

In psoriasis, skin cells are made much faster than usual, within days rather than weeks, because of faulty signals from the immune system. The extra cells pile up on the surface and form patches ². The NHS notes that you are more likely to have psoriasis if a family member has it ¹.

The scalp is one of the most common places for it to appear. DermNet estimates that psoriasis affects around 2% of people worldwide, and about 80% of them have scalp involvement ². The American Academy of Dermatology (AAD) says about half of people with plaque psoriasis will have a flare on the scalp ³.

What it looks like

• Well-defined, red, thickened patches with silvery-white scale ²
• Often at the back of the head, and it can extend past the hairline onto the forehead, ears or neck ²
• Flaking that looks like dandruff, and itching that can be severe ²
• Sometimes very thick scale that builds up like overlapping roof tiles (a pattern called pityriasis amiantacea) ²

On brown and black skin, patches may look grey, purple or dark brown rather than red, and can leave dark marks after they clear ^{1 2}. This can delay diagnosis.

Psoriasis can also affect other areas, such as the elbows, knees, back and nails, where it can cause dents and pits ¹.

Psoriasis or seborrhoeic dermatitis?

The two can look alike, and they can even occur together, which is called sebopsoriasis ². As a rough guide, psoriasis patches tend to be thicker and sharply defined, while seborrhoeic dermatitis scale is usually greasier and less defined. A doctor can tell the difference, sometimes using a magnifying tool (trichoscopy) or, rarely, a skin biopsy ². See seborrhoeic dermatitis.

Does scalp psoriasis cause hair loss?

It can. In severe cases, scalp psoriasis can cause temporary, localised hair loss ². Scratching and picking at scale can also cause hair loss ⁴. The hair loss is usually reversible; only rarely does long-standing, relapsing psoriasis cause scarring ². That is one more reason to treat it early.

What triggers flares?

Psoriasis tends to come and go, with flare-ups and calmer periods ¹. Common triggers include ^{1 2}:

• Stress
• Smoking and alcohol
• Infections, such as strep throat
• Injury to the skin, including cuts, scratches and grazes
• Certain medicines
• Harsh chemical products or soaps
• Obesity
• Hormonal changes, such as puberty, after childbirth and menopause

Sunlight usually helps psoriasis but occasionally makes it worse ².

Treatment

Scalp treatment is harder than treatment on the body because hair gets in the way. Most treatments need to be used regularly for several weeks before you see a benefit, and may need to continue to keep the scalp clear ². Lotions, gels, foams and shampoos are usually easier to use on the scalp than heavy ointments ².

Over-the-counter options

• Scale softeners with salicylic acid soften thick patches so other treatments can work ^{3 4}
• Coal tar shampoos, which can help with itch ³. They can stain hair and scalp ²

If these do not help, see a dermatologist. The AAD says that with a dermatologist's help, it is unusual for anyone to struggle to control scalp psoriasis for long, even when it is severe ³.

Prescription treatments

• Corticosteroids applied to the scalp are the most commonly prescribed treatment and work quickly on redness, swelling, itch and scale ³. Long-term use can cause side effects, so a doctor may combine them with another treatment ³
• Vitamin D analogues such as calcipotriol, often combined with a steroid ^{3 2}
• Steroid shampoos for stubborn cases ³
• For thick or resistant patches: steroid injections, light or laser treatment, and for severe psoriasis, tablets or injections that work on the whole body ^{3 2}

Treatment plans should fit your hair type and washing routine. DermNet notes that people who wash their hair less often may do better with a once-weekly wash plus a daily scalp treatment, rather than daily medicated shampoo ².

Caring for your scalp

The AAD shares these tips ⁴:

• Try not to scratch. It can make psoriasis worse, cause bleeding and lead to noticeable hair loss
• Shampoo gently. Rubbing and scrubbing tend to make scalp psoriasis worse
• Remove scale with care. Picking can cause flares and hair loss; use a scale softener instead
• Lift your hair out of the way when applying medicine, so it reaches the scalp
• Manage stress, which can worsen psoriasis

DermNet adds regular moisturising, avoiding known triggers, keeping a healthy weight, limiting alcohol and stopping smoking ².

When to see a doctor

See a doctor if you think you have psoriasis, if treatment is not working or causes side effects, or if you also have joint pain, stiffness or swelling that keeps coming back. Some people with psoriasis develop psoriatic arthritis ¹.

The bottom line

Scalp psoriasis is a long-term condition that cannot be cured, but it can be controlled. Use gentle care, soften scale instead of picking it, and see a doctor if over-the-counter products are not enough. Any hair loss it causes is usually temporary when the psoriasis is treated.

Frequently asked questions

Is scalp psoriasis contagious?

No. You cannot catch or spread psoriasis ¹.

Can scalp psoriasis make my hair fall out?

Severe scalp psoriasis, scratching and picking can cause hair loss. It is usually temporary ^{2 4}.

Can scalp psoriasis be cured?

No, but treatments can manage symptoms and keep the scalp clear ^{1 2}.

How is it different from dandruff?

Psoriasis causes thick, well-defined red patches with silvery-white scale, while dandruff is flaking without visible inflammation ^{2 5}.

Educational content. Not medical advice.