Test Your Knowledge

Dandruff occurs as a result of an overproduction of skin cells in the scalp. However, the exact mechanism of this process is unknown. It appears to be associated with an overabundance of a common skin yeast called Malassezia, but the relationship between the yeast and the skin flaking is not well understood.

The yeast feeds on oils (sebum) in the scalp. For that reason, people with oily skin and hair are more prone to dandruff. Men are also more likely to experience dandruff. This may be because men have larger sebaceous glands (glands that produce sebum). Some researchers believe male hormones may also play a role in dandruff.

People who live in certain climates may experience seasonal flare-ups when the weather turns colder and the air becomes drier, with remission occurring in the summer months. Other factors known to trigger dandruff include:

• Emotional stress
• Hormonal fluctuations (e.g., puberty)
• Infrequent hair washing
• Overuse of styling products (e.g., hair sprays, gels)

In addition, people with certain conditions may have an increased likelihood of developing dandruff. These include:

• Seborrheic dermatitis
  
  
• Acne
  
  
• Neurological conditions, such as Parkinson’s disease
  
  
• Medical conditions that stress the body, such as heart attack and stroke
  
  
• Conditions characterized by hormonal imbalances, such as polycystic ovarian syndrome
  
  
• Conditions that affect the immune system, including human immunodeficiency virus (HIV) infection