Is dandruff caused by a fungus?

Is Dandruff Caused by Fungus?

Yes, dandruff is primarily caused by Malassezia fungi (formerly known as Pityrosporum), which release irritating free fatty acids by metabolizing sebaceous triglycerides on the scalp. 1

Fungal Etiology of Dandruff

• Dandruff results from three main etiologic factors: Malassezia fungi, sebaceous secretions, and individual sensitivity 1
• The most common Malassezia species associated with dandruff include M. globosa (67.15%), M. furfur (21.70%), and M. restricta (12.15%) 2
• These lipophilic fungi metabolize sebum on the scalp, releasing free fatty acids that irritate the scalp and lead to increased skin cell turnover 1

Mechanism of Action

• Malassezia fungi feed on sebaceous triglycerides, breaking them down into free fatty acids (particularly oleic acid) 1
• These free fatty acids cause scalp irritation, leading to increased skin cell turnover and the visible flaking characteristic of dandruff 1
• The fungal component explains why antifungal treatments are effective in controlling dandruff symptoms 3

Clinical Presentation

• Dandruff presents as generalized, diffuse scaling of the scalp that can resemble the diffuse scale pattern seen in some fungal infections 4
• In some cases, dandruff may be difficult to distinguish from mild forms of tinea capitis (fungal scalp infection), as both can present with scaling without significant hair loss 4

Treatment Implications

• Antifungal agents are the first-line treatment for dandruff, confirming the fungal etiology 5
• Ketoconazole-containing products are highly effective against Malassezia species found on the scalp 6, 3
• Pyrithione zinc works by killing Malassezia fungi, thereby reducing free fatty acids and subsequently reducing scalp flaking and itch 1
• Anti-dandruff shampoos containing proven antifungal compounds show significantly better efficacy compared to regular shampoos 3

Risk Factors and Associated Factors

• Gender and age are associated with Malassezia presence, with certain demographics showing higher susceptibility 2
• Use of hair oils increases the risk of Malassezia colonization (AOR = 2.964), likely by providing additional lipid substrate for fungal growth 2
• Regular use of anti-dandruff shampoo is negatively associated with Malassezia presence (AOR = 2.782), supporting the fungal etiology 2

Important Clinical Considerations

• While Malassezia fungi are the primary causative agent, individual susceptibility plays a significant role in determining who develops dandruff 1
• The condition affects nearly half of the world's population, making it one of the most common scalp disorders 7
• Effective management requires targeting the fungal component through regular use of antifungal shampoos 7, 3