Dandruff is a less severe and chronic condition of the scalp. Dry skin flakes away from the scalp and may fall onto a person's shoulders and clothes.
In this article, we explain the difference between dandruff and psoriasis that affects the scalp. Knowing the differences can support rapid and effective treatment for both.
Although people often find it difficult to distinguish between psoriasis of the scalp and dandruff, these conditions do have different symptoms.
Dandruff is a common scalp condition that causes small pieces of dry skin to flake from the scalp. These flakes can be noticeable and may cause embarrassment if they fall on to a person's shoulders. However, the condition is not contagious or harmful to overall health.
Sometimes, what seems to be dandruff might indicate another underlying skin condition, such as seborrheic dermatitis, eczema, psoriasis, or fungal infection.
A person only needs to seek medical treatment for dandruff if it does not resolve with over-the-counter (OTC) shampoos and ointments.
This immune-mediated condition can affect any area of the scalp and will typically appear as thick, inflamed, reddish patches.
Scalp psoriasis can cause extreme itching, and the skin might become so dry that it cracks and bleeds. Scalp psoriasis can also spread from the scalp onto the face.
People should seek medical attention if they find any cracking or bleeding underneath what they believe to be dandruff.
A flaky scalp might develop as a symptom of other conditions.
- Seborrheic dermatitis, which occurs due to an overgrowth of yeast on the skin. Seborrheic dermatitis can cause the scalp to become itchy, scaly, and red.
- Tinea capitis is a fungal infection that is sometimes known as "scalp ringworm" and also causes flaking.
- Eczema is a widespread skin condition that results in dry, red, flaky skin in different areas of the body.
- Allergic contact dermatitis on the scalp can also display as flaking skin and may result from certain cosmetic products.
- Cradle cap is a type of seborrheic dermatitis. It causes yellow, greasy, scaly dandruff that often affects babies in their first 2 months of life. Symptoms usually only last for a few weeks or months. Gently washing the hair with baby shampoo can help prevent a buildup of scales on a baby's head.
Psoriasis has some specific causes, but researchers know less about the causes of dandruff.
About half of all people with plaque psoriasis will get symptoms on their scalp. Scalp psoriasis has the same underlying cause as other forms of psoriasis.
It develops when a person's immune system instructs the skin cells to grow too quickly. This misinformation causes skin cells to build upon the surface of the skin in the form of thick plaques. They develop in flares of symptoms that occur in response to environmental triggers.
Stress, extreme temperatures, and infectious illnesses can all trigger flares of scalp psoriasis.
In the United States, around 2.5% of white people and 1.3% of black people have psoriasis, according to the National Psoriasis Foundation. Males and females carry equal risk of developing psoriasis.
Psoriasis frequently begins in people who are between 15–35 years of age, though it can develop at any age. Very rarely, psoriasis may develop in infants.
Dandruff is a common scalp condition that affects around one in two people across the world.
Some people believe that dandruff is a result of poor hygiene, but this is not true.
Symptoms of dandruff seem to get worse in winter. However, scientists do not yet completely understand its root causes.
There are several treatment options available for both scalp psoriasis and dandruff.
A person with moderate-to-severe scalp psoriasis may wish to talk to a dermatologist. This is a doctor who specializes in skin conditions and can recommend appropriate treatments.
When psoriasis has involvement with the scalp, symptoms can be challenging to treat. A person with lesions on the scalp may need to try several treatments or combinations before they see significant results.
Treatments may include the following.
Severe cases of scalp psoriasis may require topical therapies, such as:
- Corticosteroids: These are the most effective topical treatments for scalp psoriasis. A dermatologist might prescribe another medication alongside steroids to reduce side effects.
- Medicated shampoos: These usually accompany a stronger treatment as part of a regimen. Shampoos containing clobetasol propionate are among the most effective shampoos for scalp psoriasis. People can safely use them every day for 4 weeks or less.
- Scale-softening agents: Ointments, creams, and lotions containing salicylic acid and urea can help soften scales, which makes removing them easier.
- Calcipotriene: This is a synthetic type of vitamin D-3 that people with scalp psoriasis often apply before bed. People sometimes combine this with a steroid to boost the effects of treatment.
- Tazarotene (Tazorac): A person with psoriasis can apply a thin layer or tazarotene before bed. They can shower off the layer when they wake up. A treatment plan might include this medication alongside a steroid.
Systemic medications target specific parts of the immune system to reduce the frequency of flares and the severity of symptoms.
For scalp psoriasis, however, doctors do not usually prescribe systemic drugs unless symptoms are severe or do not respond to other medications.
These medications include:
- Injected corticosteroids: A dermatologist can inject steroids directly into the psoriatic lesions. However, they will only be able to carry this out for a limited number of injections.
- Biologic medications: These come from living cells and target specific parts of the immune system. They can help reduce the frequency and level of skin responses to flares.
- Cyclosporine (Gengraf, Neoral, SandIMMUNE): People with severe plaque psoriasis can use cyclosporine, an off-label drug that suppresses the immune system. People normally use it to prevent the body from rejecting an organ after a transplant. However, it may be useful for people with psoriasis.
- Acitretin (Soriatane): This is an oral retinoid that manufacturers produce from vitamin A. It can slow cell growth and bring down swelling and redness.
- Apremilast: This inhibits an enzyme within the skin cells that is responsible for inflammation.
People with more severe scalp psoriasis may need to try and combine several treatments before they find one that works for them.
Off-label medications that the Food and Drug Administration (FDA) have approved for other conditions but also have an effect on scalp psoriasis include fumaric acid esters.
After repeated use, a person's psoriasis may become less responsive to the medication. If this happens, they should combine and rotate different types of treatment.
There are many different OTC shampoos for dandruff.
Some of these shampoos have slightly different instructions on how long people should lather or rinse the hair. For maximum effect, people should follow the label instructions closely.
People can try using shampoos that have different active ingredients if their first choice is not effective. Active ingredients include:
- zinc pyrithione
- salicylic acid
- coal tar
People need to be aware that coal tar may cause discoloration to hair that is not already black and make the scalp more sensitive to sun exposure
If a person's symptoms improve, then they may be able to use the shampoo less often. However, if they stop using the shampoo completely, dandruff will likely come back.
If symptoms have not improved after trying dandruff shampoos for longer than a month, a person may wish to talk to their doctor or healthcare specialist.
There are many ways that people who have scalp psoriasis or dandruff can care for their scalp. Certain steps can help to manage each condition and provide some relief from symptoms.
Scalp care for psoriasis
If a person has psoriasis, they should try not to scratch their scalp. This may be challenging, as the itching can be intense. People should also try to avoid picking at the plaques.
It is best to shampoo the scalp gently. Rubbing or vigorously scrubbing the scalp can make psoriasis worse.
Stress can act as a trigger for psoriasis and also make it worse. Finding effective relaxation techniques, such as yoga or meditation, can also help people with this condition.
Scalp care for dandruff
If a person has dandruff, they should be careful when using a dandruff shampoo that contains coal tar. This is because these sorts of shampoo can discolor light-colored hair.
The AAD recommend that white people or those of Asian descent should use regular shampoo daily and dandruff shampoo twice a week only.
The AAD suggest that black people shampoo just once a week with a dandruff shampoo.
Can stress cause dandruff?
No, stress is not a cause of dandruff. Dandruff can result for many reasons, most commonly it’s simply because of dry weather.
However, another cause is <em>Malassezia</em>, which is a yeast-like fungus that is present on the scalps of most adults and might irritate your skin more if you are stressed.Debra Sullivan, PhD, MSN, RN, CNE, COI Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.