Causes + Triggers


There is a direct correlation between having oily skin or scalp and dandruff. Malassezia, a fungus found on the skin of most people, loves the oil or sebum skin produces and thrives on it. Excessive oil production can lead to a more severe form of dandruff called Seborrheic Dermatitis.



Most people have a naturally occurring fungus called Malassezia on their scalp. They also have sebum or skin oils on their scalp. The Malassezia breaks sebum down into oleic acid. 50% of the world’s population is sensitive to oleic acid which results in dandruff. If you’re not sensitive to oleic acid, you won’t experience dandruff. Dandruff tends to run in families, indicating a genetic predisposition for chronic scalp conditions. Predisposition to this sensitivity is something that can be inherited, but it is not the only cause of dandruff.



Androgens are a group of hormones that are responsible for sexual development in both men and women. Testosterone, present in both men and women, is the most important androgen in sexual development. This is one reason many people experience dandruff for the first time during puberty. Androgens or hormones control sebaceous glands and regulate overall sebum production. The more active androgens are, the more sebum the body will produce. Since men have higher levels of testosterone, this may account for the fact that more men have dandruff than women.



An itchy, red, irritated, flaky scalp could suggest that you have an allergy to a shampoo, conditioner or hair styling product. Fragrance is most often responsible for allergic reactions. There are, however, other ingredients that may cause a dandruff-like reaction. They include paraphenyldiamine (PPD) found in hair color, propylene glycol and acrylates often used in hairsprays and formaldehyde used in smoothing or straightening products. If you think a hair care ingredient may be the culprit, consult a dermatologist for patch testing.



Food allergies can produce symptoms that affect many different parts of your body, including skin and scalp. Food allergy skin conditions range from rashes and hives to patches of dry skin. Common allergies to foods like dairy or wheat are often blamed for being dandruff-causing. An elimination diet can help identify foods that may cause or aggravate dandruff. Allergy testing is also an alternative way of finding out what foods may contribute to dandruff. There are many different types of food allergies but the "big eight" account for about 90 percent of all food allergies. They include:

EggsDairy PeanutsNuts Fish Shellfish Wheat Soy



There is a relationship between stress and dandruff. Stress weakens the immune system and disrupts the body’s delicate balance. The body responds to stress by increasing the amount of cortisol being produced in the body. This results in fewer immune cells in the body helping the immune system to ward off harmful microbes. With a compromised immune system, Malassezia (the fungus that causes dandruff) can thrive, causing a flare up or existing dandruff to worsen. Developing methods for reducing stress can help to battle dandruff and keep it under control.



As you might expect, people with skin conditions like Psoriasis and Eczema tend to have dandruff more frequently than others. Adults with Parkinson’s and other neurological illnesses are also more prone to dandruff and Seborrheic Dermatitis. Scalp conditions are also common among people living with HIV. One study found that about 50% of people living with HIV have severe dandruff or Seborrheic Dermatitis, compared to 5% in the general population. Finally, people with weakened immune systems who are recovering from a heart attack or stroke may also experience dandruff during their recovery.



There seems to be a link between alcohol consumption and dandruff. Alcohol can cause dehydration which can result in a variety of symptoms including dry skin. One of the first and most noticeable areas affected by alcohol dehydration is the scalp, and dandruff is a common result. While all alcoholic beverages can contribute to dandruff, white wine and champagne are the biggest culprits. They also are relatively high in sugar content, and sugar feeds the fungus that causes dandruff.



For those who suffer with dandruff or chronic scalp conditions, it is a year-round problem. There are, however, seasonal differences that can make scalp conditions worse. Characteristics at both ends of the seasonal spectrum contribute to possible flare ups: the cold, dry air of winter and the heat and humidity of summer.

Winter For many, dandruff tends to be worse during the dry winter months. The harsh winds, cold air and freezing temperatures are hard on skin and hair. One of the biggest challenges during the winter months is the loss of moisture and natural oils on the skin and scalp. The dryness can cause lots of flakes and itching. Heat and space heaters only further aggravate the problem, but a humidifier can help to add lost moisture to the air.

Summer Dandruff usually improves during the summer months, unless the weather is exceptionally hot and humid. There are several things that may make the summer symptoms worse. Warmer temperatures allow the dandruff-causing fungi to thrive, raising the prospect of a dandruff flare-up. The heat combined with moisture from humidity or sweat provides an ideal environment for dandruff to grow. For summer dandruff, avoid wearing hats for too long and take time to get a little sun on your scalp.