on February 19, 2025

What Causes Dandruff?

Dandruff, a condition medically known as pityriasis capitis, affects nearly half of the global adult population, making it one of the most common scalp concerns worldwide. Contrary to the popular belief that it stems from poor hygiene, dandruff is a complex scalp disorder with specific biological underpinnings. In this article, we’ll uncover the real causes of dandruff, explore the factors that contribute to its development, and provide a deeper understanding of this widespread condition.

a magnifier shows dandruff on hair

The Biological Reasons for Dandruff

Dandruff may seem like a simple issue of flaking, but it is rooted in a complex interplay of microbiological and physiological processes on the scalp. To understand why it occurs, let’s break down the key factors.

Fungal Overgrowth of Malassezia globosa

The primary culprit behind most cases of dandruff is a microscopic fungus called Malassezia globosa. This yeast-like microbe naturally resides on the scalps of most adults without causing any issues. It thrives by feeding on sebum, the natural oil secreted by your scalp's sebaceous glands.

The problem arises when Malassezia globosa proliferates. As the fungus metabolises sebum, it produces oleic acid as a by-product. In individuals susceptible to dandruff, this oleic acid penetrates the top layer of the skin, disrupting the scalp's natural barrier. This triggers an inflammatory response, leading to the irritation, itching, and increased skin cell shedding that characterise dandruff (Borda & Wikramanayake, 2015). It’s important to note that an individual's sensitivity to oleic acid is a key determinant of whether they develop dandruff, not just the presence of the fungus itself.

Excess Sebum Production

Sebum is vital for maintaining a healthy, moisturised scalp. However, when the sebaceous glands become overactive, a condition known as seborrhea, they produce excess oil. This surplus sebum creates the perfect feeding ground for Malassezia globosa to multiply rapidly.

Factors like hormonal imbalances (especially during puberty), stress, and genetics can all lead to increased sebum production. This excess oil can also cause dead skin cells to bind together, forming the oily, yellowish clumps typical of a more inflammatory form of dandruff called seborrheic dermatitis.

Accelerated Skin Cell Turnover

Under normal conditions, your scalp constantly renews itself by shedding old skin cells and generating new ones over a cycle of about 30 days. In individuals with dandruff, this process is dramatically accelerated.

The irritation caused by oleic acid prompts the scalp to shed skin cells much faster, sometimes in as little as 2-7 days. Because the cells shed so rapidly, they don't have time to mature and detach individually. Instead, they accumulate and clump together, forming the visible flakes associated with dandruff.

These three biological factors, fungal overgrowth, excess sebum, and rapid cell turnover, are interconnected. They create a self-perpetuating cycle: excess oil feeds the fungus, the fungus produces irritants, and the irritation speeds up cell turnover, leading to more flaking. Breaking this cycle is the cornerstone of effective dandruff treatment.

External and Internal Triggers for Dandruff

Dandruff doesn’t arise solely from biological processes; it’s also influenced by various external and internal factors. These triggers can worsen existing dandruff or create conditions that lead to its development.

  • Hormonal Changes: Hormones, particularly androgens, regulate sebum production. This is why dandruff often appears or intensifies during puberty. Hormonal fluctuations during other life stages, such as pregnancy or periods of high stress, can also impact scalp health.
  • Stress: High levels of emotional or physiological stress can impact overall health, including the immune system and hormonal balance. Stress can weaken the skin's natural barrier and exacerbate inflammatory conditions like dandruff.
  • Dietary Influences: While research is ongoing, some evidence suggests that diets lacking in zinc, B vitamins, and certain types of fats may contribute to dandruff. These nutrients are essential for maintaining healthy skin, and their deficiency could impair the scalp's barrier function.
  • Weather and Environmental Conditions: Dandruff often worsens during seasonal changes. Cold, dry winter air can strip moisture from the scalp, leading to dryness and flaking. Conversely, hot, humid weather can increase sweating and oil production, creating an environment where Malassezia can thrive.

woman hair with dandruff falling on her shirt

Managing and Treating Dandruff

Understanding dandruff is the first step toward managing it effectively. Treatment focuses on disrupting the biological cycle of oil production, fungal growth, and cellular turnover.

Types of Dandruff: Oily vs. Dry

Identifying the type of dandruff you have can help you choose the right treatment:

  • Oily Dandruff (Seborrheic Dermatitis): Characterised by larger, greasy or waxy, yellowish flakes that stick to the scalp and hair. It is often accompanied by redness, inflammation, and itchiness due to high sebum levels and fungal activity.
  • Dry Dandruff: Appears as small, fine, white flakes that easily fall from the scalp onto the shoulders. It is typically caused by a dry scalp, often exacerbated by cold weather or the use of harsh, drying hair products.

How to identify dandruff

For those struggling to manage dandruff with over-the-counter solutions, consulting a healthcare professional can provide valuable insights. Dermatologists typically diagnose dandruff through a combination of visual examination, patient history and scalp tests.

  • Visual Examination: Observing the scalp and flakes to distinguish dandruff from other conditions like psoriasis or eczema.
  • Patient History: Assessing factors such as diet, stress levels, and hair care routines to identify potential triggers.
  • Scalp Tests: In some cases, a scalp scraping or biopsy may be performed to rule out fungal infections or other skin disorders.

Why Some Are More Prone to Dandruff

Why do some people seem more prone to dandruff than others? The answer often lies in a combination of genetic, biological, and lifestyle factors:

  • Skin Sensitivity: Individuals with more sensitive skin may react more strongly to Malassezia by-products or other irritants.
  • Sebum Levels: People with naturally oily scalps are more likely to experience oily dandruff, as excess sebum provides an ideal environment for fungal growth.
  • Stress and Hormones: Higher stress levels or hormonal fluctuations can make some individuals more susceptible to flare-ups.
  • Hair Care Habits: Overwashing, under-washing, or using harsh products can disrupt the scalp’s natural balance, increasing susceptibility.

How Anti-Dandruff Shampoos Help

Medicated anti-dandruff shampoos are the most common and effective first-line treatment. They contain active ingredients designed to address the root causes of dandruff:

  • Antifungal agents like Piroctone Olamine, Ketoconazole, Selenium Sulphide, and Zinc Pyrithione work by controlling the population of the Malassezia globosa fungus on the scalp.
  • Keratolytic agents such as Salicylic Acid and Coal Tar help to slow down and regulate skin cell turnover, reducing the formation of flakes.

For a powerful solution that targets these causes, specially formulated products like the BioScalp Dandruff Control shampoo can effectively reduce flaking and soothe irritation by rebalancing the scalp's microbiome. Consistent use is key. Massage the shampoo into the scalp, leave it for 3-5 minutes to allow the active ingredients to work, and then rinse thoroughly.

For persistent or severe dandruff, a more comprehensive strategy may be required. Combining multiple treatments can provide enhanced relief. A complete system, such as the BioScalp Dandruff Control Kit, often pairs a medicated shampoo with conditioning treatments and soothing serums to fight flakes, calm inflammation, and restore long-term scalp health.

Check out other ways to get rid of dandruff here.

When to See a Doctor

If over-the-counter treatments don't provide relief after several weeks, or if your scalp is excessively red, painful, or swollen, it's best to consult a doctor or dermatologist. They can provide an accurate diagnosis to rule out other skin conditions like psoriasis or eczema and recommend prescription-strength treatments if necessary.

Conclusion

Dandruff is a manageable condition driven by a combination of fungal activity, excess oil, and a rapid skin renewal cycle. While internal and external triggers like stress, hormones, and weather can worsen symptoms, the key to control lies in addressing the underlying biological causes.

By identifying your dandruff type and using targeted treatments that regulate fungal growth and normalise cell turnover, you can effectively manage flaking and irritation. With a consistent and appropriate care routine, it is possible to restore balance to your scalp and maintain healthier, flake-free hair.

References

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