What is dandruff and why does it occur?

What dandruff actually is

Dandruff is a very common scalp condition in which there is a massive shedding of cells from the outer (corneal) layer of the scalp skin. All skin renews itself constantly, and it is normal for cells to die and shed in the form of tiny, invisible flakes.

In people with dandruff, this shedding becomes visible and excessive. The flakes can appear as white or yellowish scales on the scalp and hair. In many cases, dandruff is accompanied by other symptoms such as:

• itching
• mild redness
• a feeling of irritation or discomfort on the scalp

Although dandruff is not a serious disease in itself, it can be persistent, socially annoying and sometimes a marker of an underlying scalp tendency, such as seborrhoeic dermatitis.

How dandruff develops on the scalp

Dandruff usually arises from an interaction between several factors:

• the way the scalp produces and distributes sebum (natural oil)
• the presence and activity of micro-organisms, particularly certain yeasts that form part of the normal scalp flora
• the individual sensitivity of the skin and its tendency to become inflamed

When this balance is disturbed, the renewal of the scalp’s outer layer accelerates and becomes disorganised. Cells clump together and detach in visible scales instead of microscopic fragments.

Dry vs. greasy dandruff

Some people mainly notice small, dry, white flakes that fall easily from the scalp and hair. Others have greasy dandruff, with larger, more adherent scales that may appear yellowish and stick to the scalp surface or hair, often in the context of an oily scalp.

Greasy dandruff is often associated with overactive sebaceous glands (excess oil production) and may be related to conditions such as seborrhoeic dermatitis. In these cases, the scalp can look shiny or oily, and flakes are more compact.

Factors that can contribute to dandruff

Dandruff does not have a single universal cause. Several elements can contribute to its appearance or make it worse.

Sebum and micro-organisms

Overactive sebaceous glands, especially in greasy dandruff, create an environment in which certain yeasts that live naturally on the scalp may become more active. In people who are sensitive, this situation can trigger irritation and increased flaking.

Genetic and individual factors

Family history and individual skin characteristics also play a role. Some scalps are more reactive or prone to flaking and redness than others, even with similar external conditions.

Products and external irritants

The use of alkaline soaps or shampoos that are too harsh for the scalp can damage its surface barrier and disturb normal renewal. In some people, dandruff symptoms may also be aggravated by:

• very strong shampoos used frequently
• certain hair dyes
• excessive use of gels, sprays or fixatives, especially when they are not washed out properly
• exposure to dust or other irritant particles

In a few cases, fungal infections (mycosis) or other scalp conditions can produce scaling that resembles or overlaps with dandruff. When in doubt, professional assessment is recommended.

Seasonal changes, stress and lifestyle

Many people notice that dandruff worsens at specific times of the year. Cold and dry winters and, for some, the autumn months are classically associated with more visible flaking and discomfort. Environmental changes, heating, lower humidity and other factors may influence this.

Stress is another recognised aggravating factor. While stress is unlikely to be the only cause, it can alter skin balance and make pre-existing tendencies more evident.

When dandruff needs professional evaluation

Mild dandruff that responds to appropriate care is common. However, it is advisable to seek a professional opinion if:

• the flaking is very intense or persistent
• there is marked redness, oozing or pain
• itching is severe or interferes with daily life
• scaling extends beyond the scalp (for example to the eyebrows, sides of the nose or ears)
• over-the-counter products have little or no effect

An authorised Simone Trichology hair centre can distinguish between simple dandruff, seborrhoeic dermatitis, psoriasis, fungal infections and other scalp conditions, and can advise on the most suitable care and, where necessary, medical referral.

Dandruff is, in many cases, manageable, but understanding what it is and which factors are influencing your scalp is essential to choosing the right strategy instead of simply hiding the flakes.