October in Vienna tends to follow the same script. The radiators are finally warm, a long hot shower feels like the best part of the evening, and the scarf is back on its hook by the door. Then, a week or two later, small changes appear. Your scalp itches for no obvious reason, tiny white flakes show up on a dark sweater, and your hair crackles with static and sticks to everything it touches.

The first thought is usually "dandruff". The second is "I should wash my hair more often". Sometimes that's the right call. Quite often, though, it makes things worse. Here's why.

What heating does to the air

It starts with simple physics. Cold outdoor air holds very little moisture, and once it's warmed inside your home, it becomes drier still. If air at 10 degrees Celsius and 50% humidity is heated to 23 degrees, its relative humidity drops to around 20%. For comparison, the comfortable range indoors is roughly 40 to 60%, and during the heating season humidity often falls far below that.

Skin responds quickly. In a laboratory study on a model of human skin, just one hour of exposure to low-humidity air raised transepidermal water loss, the process by which moisture evaporates through the skin's outer layer. The researchers suggest that repeated exposure to dry air, day after day, is what gradually leads to dry skin.

Your scalp is no exception. It's the same skin as on your face, just hidden under your hair, and we pay it far less attention.

Dry scalp or dandruff: how to tell

They can look alike, but the causes are different, and so is the care.

A dry scalp comes from a lack of moisture and lipids, the fats that hold water in the skin. As dermatologists describe it, dry scalp flakes tend to be smaller and drier, while dandruff flakes are often larger, greasier and yellowish. The scalp feels tight, and you'll often notice dryness elsewhere too: on your hands, shins or lips.

Dandruff is linked to excess oil and a yeast called Malassezia, which normally lives on everyone's skin. With dandruff, the scalp tends to feel oily, flakes cling near the roots, and there may be some redness.

One more difference is worth knowing: washing too often can worsen a dry scalp, while washing too rarely can worsen dandruff. That explains why "wash more" helps some people and backfires for others.

To complicate things, the two can overlap. Dermatologists note that many people with what they believe is a dry scalp actually have undiagnosed seborrhoeic dermatitis, and dryness can also be linked to eczema. If you're unsure, it's worth having a doctor take a look.

Three common misconceptions

"It itches, so it must be dirty." With a dry scalp, frequent washing strips away what little protective lipid is left, and the itching can actually get worse.

"An anti-dandruff shampoo fixes any kind of flaking." If the cause is dryness rather than yeast, dandruff treatments won't help and may even make the flakes worse.

"Hot water soothes the itch." The relief lasts only as long as you're standing under the shower. The American Academy of Dermatology advises using warm rather than hot water and keeping showers to five to ten minutes, especially when the air is dry.

Ingredients worth looking for

Niacinamide (vitamin B3) helps the skin rebuild its own protective barrier. Research shows it increases the production of ceramides and other lipids between the cells of the skin's outer layer. Think of ceramides as the mortar between skin cells that keeps water from escaping. Niacinamide is well tolerated and suits a sensitive scalp, though its effect builds over time rather than stopping an itch instantly.

Panthenol (provitamin B5) is one of the best-studied soothing ingredients. In the skin it converts to vitamin B5, and according to a review of clinical data it improves hydration of the outer skin layer, reduces water loss and helps keep skin soft and supple. The same review notes that dexpanthenol care noticeably improved dryness, scaling and itching in irritated skin over three to four weeks. It's especially useful when the scalp is irritated from scratching.

Piroctone olamine is the one to look for if your flakes sound more like dandruff. It's an antifungal ingredient that helps keep Malassezia in balance. In a study by P&G researchers, a piroctone olamine shampoo shifted the scalp microbiome of people with dandruff toward a healthy, dandruff-free state. It doesn't have to be the star of a product; it works well as part of everyday care.

For the lengths: complexes that support hair structure. Dry air dries out the hair itself, not just the skin. Moisture helps an electrical charge dissipate, so in dry air static becomes far more noticeable, and friction from wool scarves and hats adds wear and tear. Hair that took a beating from summer sun or lightening is especially vulnerable. One interesting option here is a complex of itaconic acid and arginine with linseed and chia extracts. In a study published this year, this complex, combined with panthenol, was evaluated for repairing chemically damaged hair, where it helps reinforce bonds inside the fibre and restore the cuticle. One caveat: the ingredient was tested on its own, on bleached hair, not as a finished product.

What you can do today

• Check the humidity at home. A hygrometer is inexpensive. If it reads below 40%, a humidifier helps, especially in the bedroom.
• Turn the water down a little and keep your showers shorter.
• Don't over-dry your scalp. If dryness is the issue, washing every other day or less often is usually enough.
• Use conditioner on the lengths, and if yours is also made for the scalp, work a little in at the roots.
• Protect your hair from friction. Silk or cotton scarves and pillowcases create less static than synthetics or coarse wool.
• Try not to scratch. Tiny abrasions only add to the irritation.

See a dermatologist if your scalp is red or painful, if crusts appear, if the flaking spreads to your eyebrows, behind your ears or around your nose, or if nothing changes after two or three weeks of gentle care. If you've also noticed more hair on your brush lately, our article on autumn hair shedding explains what's normal and what isn't.

If you're choosing care for the season

It helps to split the job in two: care for the scalp, and care for the lengths.

For the scalp, look for formulas with niacinamide and panthenol. Both are in the RAVI Vitality Line Shampoo, while the Vitality Conditioner adds piroctone olamine and betaine, a plant-derived hydrating ingredient. The Vitality Spray, which contains alcohol and a warming ingredient, is best added once any irritation has calmed down.

For the lengths, look for care that combines itaconic acid, arginine, linseed and chia with proteins and panthenol. That combination is used across the RAVI Hair Repair 2.0 Line, and it's especially worth considering if summer or colouring has left your hair porous and quick to lose moisture.

One last thing

The heating season will last until spring. The good news is that your scalp usually doesn't ask for much: a little more moisture in the air, slightly cooler water, and care that rebuilds its barrier instead of stripping it.