Dandruff
Dandruff is flaking and itching of the scalp caused by low-grade inflammation. It is the mildest form of seborrheic dermatitis. It is not caused by a dirty or a dry scalp, and it settles quickly with the right shampoo used the right way.
Key facts
Dandruff at a glance.
Typical signs
White or yellow flakes
Common locations
Scalp
Expected course
Recurring flares
Treatment options
Medicated shampoo
What is it?
Top things to know about Dandruff
- It is excessive scalp flaking. Dandruff can come with itch.
- It sits within seborrheic dermatitis. It is often seen as a mild, scalp-only form.
- Several factors contribute. Malassezia, barrier changes, sebum and susceptibility all play a part.
- Medicine must reach the scalp. Treatment works on the scalp, not the hair lengths.
What it looks like
What Dandruff looks like
Dandruff is flaking of the scalp skin. The flakes are white or grayish, can be small and dry or larger and oily, and often show on dark clothing. The scalp may itch, but it is not usually red or inflamed. Dandruff tends to come and go, and is often worse in winter and with stress. When redness and greasy yellow scale appear, it has usually progressed to seborrheic dermatitis.
White flakes
Loose flakes on the scalp.
Flakes on clothing
Visible on dark shoulders.
Itchy scalp
Mild itch, no rash.
Where it shows up
Dandruff affects the scalp; the map marks the scalp rather than showing flakes.
Hairline and temples
Areas at the front of the scalp.
Scalp and behind the ears
Locations on the back of the head.
On different skin tones
Dandruff on different skin tones
Dandruff looks similar on all skin tones. On brown and Black skin, flakes can be more visible against the scalp, and people who wash their hair less often to protect curls may notice more buildup. Frequent use of drying shampoos can make coiled hair brittle, so medicated shampoos are often applied to the scalp only.
What happens in Dandruff?
Dandruff involves uneven shedding of the scalp's outer skin cells. The interaction between scalp oils, Malassezia yeast and individual skin sensitivity contributes to visible flakes, usually with little obvious inflammation.
- Loose flakes become visible: Dandruff usually has little visible inflammation.
- Surface yeast and oils interact: Malassezia is part of the scalp environment.
- The outer layer sheds unevenly: Skin sensitivity and turnover contribute.
Causes and triggers
What causes Dandruff
Causes
Why it happens
Dandruff is flaking caused by an overgrowth of Malassezia, a yeast that lives on everyone's scalp, and the scalp's reaction to it.
Risk factors
Raise the odds
- Oily scalp
- Teen to middle age
- Male sex
Triggers
Bring it on or make it worse
- Cold, dry weather (Strong link)
- Stress (Possible)
- Washing hair less often (Possible)
When it usually starts
When it usually starts
Dandruff
Usually begins after puberty and may come and go through adult life.
Daily care
Daily care for Dandruff
Wash more often during a flare
Removing oil removes the yeast's food.
Soften thick scale before treating it
An oil or salicylic acid for an hour lifts it.
Adjust moisturizing and indoor humidity during dry weather
Dry air makes flaking obvious.
Allow the label’s contact time before rinsing medicated shampoo
Follow the product-specific contact time. Longer exposure is not always better and may irritate.
Avoid: Washing less often when it flares
More oil means more yeast.
Avoid: Heavy oils, pomades and greases
They feed the yeast.
Avoid: Scratching and picking off scale
Damages the barrier, restarts the itch.
Avoid: Sweat, hats and helmets
Trapped heat and moisture.
Avoid: Product build-up
Dry shampoo and styling products mix with oil.
Avoid: Stress, illness and poor sleep
Not a cause, but flares track them.
Avoid: Harsh scrubbing and very hot water
Leaves the scalp sore, the yeast untouched.
Avoid: Stopping the shampoo as soon as it works
Maintenance, not a course.
Treatments
Treatments for Dandruff
Ketoconazole
The 1 percent shampoo on the shelf is a proper antifungal and one of the most effective things you can buy for dandruff. Twice a week during a flare, then once a week to hold it. Pairing it with zinc pyrithione and alternating the two tends to keep working better over months than either one used alone.
Pyrithione Zinc
The workhorse dandruff shampoo: it reduces the yeast and calms the scalp, and it is gentle enough to keep using for years. Part the hair, work it into the skin rather than the lengths, and leave it on for five minutes. It is a good choice for color-treated, gray or relaxed hair because it does not discolor.
Selenium Sulfide
Reduces the yeast and also slows how fast scalp cells shed, which makes it useful when the flaking is heavy. Rinse it thoroughly. The catch is color: it can discolor light, gray, relaxed or color-treated hair, so zinc pyrithione or ketoconazole is usually the better pick for those.
Coal Tar
Works by slowing the shedding rather than by treating the yeast, so it suits thick, heavy flaking more than a mildly itchy scalp. It smells strongly and it stains light hair and fabric, which is why most people use it only during a flare. It is also useful when scalp psoriasis is in the picture too.
Salicylic Acid
This one lifts scale rather than treating the cause. It is the right choice when the scale is thick and stuck down and other shampoos cannot reach the skin underneath. Use it first to clear the way, then follow with an anti-yeast shampoo — on its own it will not stop the dandruff coming back.
Tea Tree Oil
A 5 percent tea tree shampoo did beat a plain shampoo in one small trial, so it is not nothing. It is weaker than the standard actives and there is much less behind it. It is also a common cause of allergic contact dermatitis, so if the scalp becomes more itchy and irritated on it, that is a reason to stop rather than to persist.
Ketoconazole
Ketoconazole 2% shampoo. Double the strength of the version on the shelf, and the usual first prescription when a month of over-the-counter shampoo has not shifted it. Twice a week for a month, five minutes on the scalp each time. Once it is clear, most people drop back to an over-the-counter shampoo for maintenance rather than staying on this.
Ciclopirox
Ciclopirox shampoo. A different antifungal, and the usual next step when ketoconazole has stopped working or was never tolerated. It is used two or three times a week in the same way, with contact time on the scalp. Rotating it with a zinc pyrithione shampoo is a common way to keep a stubborn scalp under control.
Clobetasol
Clobetasol Propionate. A potent steroid, prescribed for the scalp as a solution, foam or shampoo, that settles a red, sore, intensely itchy flare within days. It is for short bursts of two to four weeks, not for keeping on hand. It does nothing about the yeast, so the medicated shampoo carries on alongside it and takes over afterwards.
Zoryve
A newer non-steroid foam approved for seborrheic dermatitis, used once a day on the scalp and face. It calms the inflammation without the thinning that comes with long-term steroid use, which makes it a reasonable option for people who keep needing steroid courses. Cost and insurance are usually the limiting factor.
Protopic
A non-steroid ointment used mainly where dandruff has spread onto the face — the eyebrows, the creases beside the nose, behind the ears. It calms the same inflammation without thinning that thin skin, which matters when the area needs treating on and off for years. It stings for the first few days. It is awkward to apply in hair, so it is rarely the choice for the scalp itself.
Fluconazole
An antifungal tablet, occasionally used for a short course when seborrheic dermatitis is severe, widespread, or not responding to anything applied to the skin. Ordinary dandruff never needs it. It also does not keep it away — shampoo maintenance still has to carry on afterwards — and it interacts with a number of common medicines.
Outlook
What to expect with Dandruff
Dandruff comes in waves - quiet stretches broken by flares. It can carry on for decades without getting steadily worse, and it follows a rough arc through life.
- 1
Babies · First weeks or months of life
It looks alarming, does not itch, and clears on its own. It is not adult dandruff and rarely needs medicated treatment.
- 2
After puberty · Teenage years
Dandruff begins after puberty, and the teenage years open its most active stretch.
- 3
Teens to middle age · The most active years
Cold air, indoor heating and less sunlight all seem to matter, and summer is usually easiest. Flares also follow illness, poor sleep and stress.
- 4
Once treated · Two to four weeks, then ongoing
Flaking and itch usually settle within two to four weeks, and come back within a few weeks of stopping. That is not failure - it is why dandruff is maintenance, with a medicated shampoo once or twice a week even when the scalp looks normal.
Complications
Complications
- Associated concerns
Dandruff is a mild scalp form of seborrhoeic dermatitis. Itching and flaking can recur; marked inflammation or persistent symptoms may indicate a condition needing a different treatment.
When to get help
When to get help
When to seek care
Seek assessment for persistent symptoms despite dandruff shampoo, marked redness, pain, crusting or patchy hair loss.
Lookalikes
What else could it be?
Scalp Psoriasis
Scalp psoriasis has thicker scale and clearer edges and may cross the hairline. Dandruff has softer edges and stays on the scalp.
Head Lice
Dandruff flakes slide off hairs easily. Lice eggs are firmly attached, and lice often cause stronger itching behind the ears and at the neck.
Ringworm
Dandruff causes general flaking. Scalp ringworm can leave one scaly patch with broken or missing hairs, especially in children, and needs medical treatment.
Questions
Questions you might be asking.
Is dandruff caused by a dry scalp?
Usually not. It is commonest on oily scalps, and the yeast behind it feeds on that oil. The scalp can feel dry and tight because it is inflamed and the barrier is disrupted, which is not the same as being short of moisture. Treating it as dryness makes it worse.
How often should I wash my hair if I have dandruff?
More often than you otherwise would, at least during a flare, because washing removes the oil the yeast lives on. If frequent washing damages your hair, change how you wash rather than how often - medicated shampoo straight onto the scalp, five minutes, condition only the lengths.
Does dandruff cause hair loss?
Not permanently. A very itchy, inflamed scalp that gets scratched or picked sheds more hair for a while, and that recovers once the inflammation settles. Thinning or bald patches need their own assessment, not a stronger shampoo.
Why did my shampoo stop working?
Usually one of two things. Either contact time slipped and it is being rinsed straight out again, or the scalp has stopped responding to that active. Rotating two medicated shampoos, such as zinc pyrithione and ketoconazole, tends to keep working.
Is dandruff related to the flaky redness around my nose and eyebrows?
Yes - the same condition in a different place. Seborrheic dermatitis affects the oily areas of the body, and the scalp is the most obvious one. The face usually responds to a gentle antifungal cream or a short course of a mild anti-inflammatory prescribed for that area, not to shampoo left on the skin.
Can I use medicated shampoo on colored or chemically treated hair?
Generally yes, but the active matters. Selenium sulfide and coal tar can discolor light, gray, relaxed or color-treated hair. Zinc pyrithione and ketoconazole are the usual choices, and conditioning the lengths limits drying of the hair shaft.
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