When you get an itchy, scaly scalp it’s natural to assume that it’s dandruff. But it isn’t always: It could be another skin condition, like scalp psoriasis.
It’s important to know the difference. In this article, I’ll explore the symptoms of these two conditions, give you tips on how to tell the difference, and talk about prevention, treatment, and how each is diagnosed.
I’ll also tell you when to see a doctor about an itchy, flaky scalp.
Psoriasis vs. Dandruff
Psoriasis is an autoimmune inflammatory condition. It happens when the immune system begins to see the skin as a pathogen and attacks the skin.
When this happens, the skin rapidly tries to repair itself, with new skin cells forming before others can slough off. This results in scaly, itchy patches that build up. These are known as plaques.
Dandruff is a condition where dry skin flakes off the scalp. Unlike psoriasis, dandruff is not driven by an immune problem. It occurs when the body over-responds to a normal type of yeast that lives on the surface of the skin. This leads to excessive production of skin cells, which leads to more flaking.
Sometimes people who have dandruff may also have dry skin elsewhere on the body.
While the symptoms of psoriasis and dandruff may seem the same to someone without either condition, they do produce unique symptoms.
Learning how to tell them apart can help you take care of your scalp and avoid unnecessary side effects.
Psoriasis can affect nearly any area of the body. When it affects the scalp, it can appear anywhere on the scalp, back of the neck, behind or around the ears, or on the forehead.
The skin may look thicker and may appear reddish, white, or silver.
Typical symptoms of scalp psoriasis include:
- Scaly patches that itch
- Burning or tingling sensations on the scalp or where plaques form
- Temporary hair loss in places where patches are thickest
If cracks or bleeding are noticed around the patches, seek medical care. Sometimes psoriasis patches can get infected because of itching.
This requires separate and urgent medical care to avoid further complications.
Dandruff is common, affecting the scalp by causing an excessive build-up of dry skin that appears as “snow-like” flakes that may fall on or around the shoulders. The condition, while embarrassing for some, is not a result of poor hygiene and is not contagious.
Symptoms of dandruff primarily involve flaky dry skin flakes. If there is itching, burning, or other symptoms, see your medical provider, since it may be something other than dandruff.
Several conditions may mimic some symptoms of either dandruff or psoriasis.
If you develop any new patches of flaky skin or rashes, see a medical provider to get a proper diagnosis.
- Seborrheic dermatitis: In some cases, what seems to be dandruff may actually be caused by seborrheic dermatitis, a type of scalp eczema. Instead of dry skin flakes, this type of scalp condition is usually patchy and flaky, but with red or yellow oily patches that seem stuck to the scalp instead of easily flaking off. Seborrheic dermatitis may be more common in people who have eczema elsewhere on the body.
- Eczema (atopic dermatitis): While seborrheic dermatitis can affect the scalp, other types of reddish eczema rashes may appear on the face, behind the ears, at the back of the neck, or even on the scalp. Since this can appear elsewhere on the body, it may make people think they have psoriasis. Eczema is not an autoimmune disorder, though it has roots in genetics, immune dysfunction, and barrier problems with the skin. People who have eczema may be more likely to have autoimmune disorders or food allergies.
- Fungal infection: There are many types of fungal infections that can affect the scalp. Tinea capitis, also known as ringworm, can cause itching and flaking. While it appears as a red ring, it does not have anything to do with worms and is not caused by poor hygiene. It is highly contagious, unlike psoriasis, dandruff, or eczema.
Understanding the difference between psoriasis and dandruff can help you know what may be avoided and what cannot.
There is no way to prevent psoriasis. It is an autoimmune disease and there is no cure, but it is possible to have times of remission when flares are not active and there are no symptoms. Psoriasis most commonly develops in older adolescents or adults up to around age 35, but it can develop in anyone at any age.
Dandruff is preventable, though some people may be more prone to it than others. A dandruff shampoo can prevent flakes from building up.
If you do not have dandruff, but have eczema or psoriasis, dandruff shampoo could irritate your scalp. If you are prone to dandruff, wash your hair at least 2-3 times per week, and more frequently if you have a very oily scalp or thick hair.
There are treatment options for both kinds of scalp conditions. But since they are very different, one treatment option won’t work for the other.
An accurate diagnosis is important to make sure you are getting the right kind of treatment.
Psoriasis is treated in a variety of ways, depending on its level of severity.
There is no cure, but some treatments can minimize symptoms and relieve pain.
Treatment options include:
- Topical creams
- Aloe vera
- Topical steroids
- Injectable steroids
- Biologic drugs
- Systemic drugs
In some cases, multiple treatments may be used at the same time, or may be alternated, to provide the best results.
Dandruff is primarily treated with special medicated dandruff shampoo. There are many options available, and some active ingredients may work better for some than others.
OTC dandruff shampoo active ingredients include:
- Salicylic acid
- Coal tar
- Zinc pyrithione
Each type of shampoo or active ingredient has its own instructions.
Follow them closely.
Overusing one product or type of ingredient may irritate the scalp or cause the product to be less effective.
Most people can tell if they have dandruff without seeing a doctor or dermatologist. However, if you notice anything more than just a few white flakes on your shoulders, be evaluated to be sure.
Psoriasis is often typically diagnosed by a physical examination.
In some cases of more severe psoriasis, a doctor may do a small skin biopsy to ensure the diagnosis is correct and that an infection is not causing the symptoms.
When to See a Medical Professional
If your scalp develops a new rash, starts itching, or you have dandruff that seems to worsen even if you are using shampoo, see a medical provider.
If it is just dandruff, a dermatologist may prescribe a stronger, prescription-strength shampoo. But if it is psoriasis, you may need a steroid or other treatment.
Psoriasis can spread to other parts of the body, causing more inflammatory symptoms.
If left untreated and unaddressed, it can worsen other health conditions or lead to complications down the road.
If psoriasis advances to psoriatic arthritis or other conditions, you may need to be referred to a specialist like a rheumatologist, who specializes in inflammatory immune disorders.
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Frequently Asked Questions
K Health has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical associations. We avoid using tertiary references.
Seborrheic Dermatitis and Dandruff: A Comprehensive Review. (2016).
A brief summary of clinical types of psoriasis. (2016).
Dandruff, cradle cap, and other scalp conditions. (2016).
Histopathological Differential Diagnosis of Psoriasis and Seborrheic Dermatitis of the Scalp. (2016).
Tinea capitis. (2021).
Psoriasis (overview). (2013).