At first glance, the symptoms of scalp psoriasis and dandruff may seem almost the same. Both conditions can cause flaky, itchy scalps. But beyond their most apparent effects, the two have distinctly different definitions, symptoms, and recommended treatments.
If you’ve started noticing changes to your scalp health, you may wonder which of the two conditions you have. Here’s a rundown of the major differences between scalp psoriasis and dandruff.
Scalp psoriasis is a chronic inflammatory skin condition that occurs on the scalp. It causes symptoms such as flaking, dry skin, redness, and itching. While symptoms most commonly appear under the hairline, they can extend onto the forehead, the back of the neck, or behind the ears.
|Psoriasis on face and scalp: causes, symptoms, and treatments|
As its name suggests, scalp psoriasis is a particular type of psoriasis — a chronic condition whose symptoms occur when the body produces skin cells too quickly. Rather than shedding, these skin cells adhere to the top of skin, building up into silvery-white, scaly patches that flake off.
Head-specific psoriasis is relatively common for those with the skin condition: 45 percent to 56 percent of people with psoriasis experience symptoms on their scalp.
Dandruff is a form of seborrheic dermatitis — a subtype of eczema — and a common chronic condition that causes rashes, crusting, and a reddish color on the skin.
Dandruff is significantly more common than scalp psoriasis, as it affects roughly half of the general population.
From far away, dandruff flakes may look similar to a mild case of scalp psoriasis. However, the two are distinct when viewed up close. Dandruff flakes are typically thinner, with less-defined edges than psoriasis scales. Dandruff flakes also tend to be yellow or white, rather than the silvery color characteristic of psoriasis flakes.
There are notable differences between the symptoms of scalp psoriasis and dandruff, beyond the color, shape, and texture of their respective flakes.
Not all people experience psoriasis in the same way. According to the American Academy of Dermatology Association, symptoms can vary from scaling (fine skin flaking) that resembles mild dandruff to thick, crusted skin plaques that span the entire scalp.
Scalp psoriasis can be quite uncomfortable. In a 2014 survey of nearly 3,500 people with psoriasis, 43 percent of respondents reported that itchiness was “the most bothersome symptom of their psoriasis.” As one member of MyPsoriasisTeam described, “It feels good to scratch, but [you] end up with a dandruff-looking pile on your clothes.”
Scratching can have another frustrating impact: temporary hair loss. If a person scratches their dry scalp or forcibly removes itchy scales, they may inadvertently lose hair in the affected areas.
This very experience led another MyPsoriasisTeam member to learn of their diagnosis: “I just found out I have psoriasis because I have a huge round spot on the back of my scalp, and it's so itchy!” they shared. “My dermatologist told me what I was already pretty sure of.”
Fortunately, these patches are usually temporary, and hair will often regrow when the inflammation of the psoriasis resolves.
Along with its characteristic flaking, dandruff may also cause an itchy scalp, as well as scaling and crusting in infants with a skin condition known as cradle cap. The signs and symptoms of dandruff may worsen during times of stress and in cold, dry weather.
Although you may immediately associate dandruff with the scalp, it can occur on other areas of the upper body, including the eyebrows, beard, mustache, and central chest. Generally, seborrheic dermatitis tends to impact oily areas, and these parts of the body can accumulate oil easily.
Researchers do not fully understand the exact causes of either psoriasis or dandruff, but there are differences in what’s known.
Doctors know that psoriasis is an immune-related disease. As with other forms of psoriasis, scalp psoriasis occurs when dysfunction in the immune system causes inflammation, resulting in scaly plaques and, in some instances, arthritis of the joints.
Normally, the body produces new skin cells in the deepest layer of skin. These cells then rise to the surface of the skin over the course of three to four weeks. For people with psoriasis, this timeframe is shortened to around three to seven days. The rapid turnaround causes immature cells to accumulate on the skin’s surface, creating the flaky, itchy patches covered with silvery scales that are characteristic of psoriasis.
Learn more about the causes of psoriasis.
The cause of dandruff isn’t entirely clear either. Research has suggested that several different factors work together to cause dandruff, including:
According to the Cleveland Clinic, certain environmental and lifestyle factors can also worsen existing dandruff cases. These include:
The diagnostic processes for scalp psoriasis and dandruff are relatively similar. In both cases, a doctor will ask questions and examine the hair and scalp for telltale signs of a certain condition.
If a doctor suspects scalp psoriasis, they may also perform a biopsy (take a small skin sample for analysis) on the affected area to rule out other skin conditions and confirm their diagnosis. If scalp psoriasis is suspected, the rest of the body should be examined for other areas of psoriasis.
Although some medications for scalp psoriasis and dandruff may overlap, treatment plans for each condition are distinct. Always talk to your doctor to determine which medications are best for you.
Addressing scalp psoriasis can be somewhat difficult, due to its location on the body.
Hair can complicate treatment for scalp psoriasis. As one research team described in a report for the journal Psoriasis: Targets and Therapy, hair doesn't just complicate the application and penetration of medications to affected areas. It also impacts the likelihood a person will stick to their treatment plan. During the study, individuals commonly complained of the greasy effects of their medications and the difficulty of removing products from their hair. (Tar shampoo, for example, is known to discolor lighter-colored hair.)
That said, topical treatments are currently used as first-line treatment in many people with scalp psoriasis. Those with more moderate to severe cases may also need phototherapy (light treatment) or a type of medication known as biologics.
Topical corticosteroids (anti-inflammatory drugs) have proven the most effective treatment for scalp psoriasis in clinical trials and are the most commonly prescribed treatment. These medications are available as over-the-counter or prescription lotions, oils, gels, foams, soaps, shampoos, and creams.
Other common topical treatments for scalp psoriasis include salicylic acid in 5 percent to 10 percent concentrations, which offers a keratolytic (scale-softening) effect. Coal tar and coal-tar shampoo can offer anti-inflammatory and anti-itch benefits. Shampoos containing Nizoral (Ketoconazole) and selenium sulfide can also be helpful.
A dermatologist may prescribe phototherapy, a treatment that involves regularly exposing the skin to ultraviolet light under medical supervision.
Phototherapy can help:
This treatment is more difficult to apply to the scalp, due to hair coverage.
Systemic treatments target the widespread effects of psoriasis on the body. These are not typically used for scalp psoriasis unless it is particularly severe or hasn’t responded to other forms of treatment.
The drug Otezla (Apremilast), as well as certain types of disease-modifying antirheumatic drugs (DMARDs) known as biologics, have been found to improve the symptoms of scalp psoriasis in clinical trials. Biologics that may be prescribed include Enbrel (Etanercept), Humira (Adalimumab), and Inflectra (Infliximab-dyyb). Other systemic medications that have been studied in clinical trials for scalp psoriasis include Stelara (Ustekinumab), Taltz (Ixekizumab), and Cosentyx (Secukinumab). Most biologics are injected subcutaneously (into a layer of fat between the skin and muscle).
For mild cases of dandruff, clearing up flakes may be as simple as doing a daily wash with a gentle shampoo to remove excess oil and skin-cell accumulation. If that doesn’t do the trick, you may want to try medicated shampoo.
There are many anti-dandruff shampoos available, including:
If you aren’t sure which shampoo is best for you, or if the shampoos you’ve used don’t appear to be working, talk to your doctor. Keep in mind that shampooing won’t be an instantaneous fix and that you may need to try a variety of shampoos before finding one that works well for you.
Be careful, as some shampoos may have a harsher impact on your skin. Mayo Clinic advises that you stop using a product if you develop itching, stinging, redness or burning. Seek immediate medical attention if you experience an allergic reaction, such as a rash, hives, or difficulty breathing.
In short: yes. While having both psoriasis and dandruff is relatively rare, it is possible to have sebopsoriasis, a condition in which psoriasis and seborrheic dermatitis (dandruff) occur simultaneously. If you have sebopsoriasis, you will experience the symptoms of both conditions. You may see white and silver flakes, itchiness, and scaliness. That said, if you think you may have both conditions, check with your doctor to get the right diagnosis and develop a tailored treatment plan.
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