Dandruff is a common scalp condition that results in the shedding of dead skin cells, which appear as white or yellowish flakes in the hair and on clothing. While people of all ages can experience dandruff, it is most common from adolescence through middle age. The condition is not contagious and is not a direct result of poor hygiene. Infrequent hair washing can make flaking more obvious, but it does not cause the underlying issue.
Causes of Dandruff
The development of dandruff is linked to an overgrowth of a yeast-like fungus called Malassezia globosa. This fungus is naturally present on the scalp of most adults, where it feeds on the natural oils, or sebum, from hair follicles. For many individuals, this fungus causes no problems. However, in some people, the body has a heightened sensitivity to Malassezia, triggering an inflammatory response that accelerates the turnover of skin cells, causing them to accumulate and shed as visible flakes.
Another cause is seborrheic dermatitis, a chronic skin condition that leads to irritated, oily, and scaly skin. Seborrheic dermatitis not only affects the scalp but can also appear on other oily areas of the body, such as the face, chest, and back. Other factors can contribute to or worsen dandruff. Hormonal changes can increase sebum production, creating a more favorable environment for Malassezia. Stress and certain medical conditions that affect the nervous or immune systems can also increase susceptibility.
Dandruff Versus Dry Scalp
Distinguishing between dandruff and a dry scalp is an important step toward finding an effective solution. While both conditions can cause an itchy scalp and flaking, their appearance and origins differ.
Dandruff is caused by an excess of oil on the scalp. This contributes to the formation of larger flakes that may appear yellowish or white, and the scalp itself often looks oily, red, and scaly.
A dry scalp, conversely, is the result of insufficient moisture. This lack of hydration leads to skin that is irritated and sheds small, white, and dry flakes. It often occurs when the skin loses too much water, which can be exacerbated by cold, dry weather or the use of harsh hair care products. Individuals with a dry scalp may notice that the skin on other parts of their body is also dry.
Over-the-Counter and Home Management
A variety of over-the-counter (OTC) shampoos are available to manage dandruff, each containing different active ingredients that work in specific ways.
- Pyrithione zinc possesses antibacterial and antifungal properties that help control the Malassezia fungus.
- Selenium sulfide slows the rate at which skin cells turn over and also helps to control the fungus.
- Ketoconazole products are specifically designed as antifungal treatments to eliminate the yeast on the scalp.
- Shampoos with salicylic acid can help exfoliate the scalp, though they may sometimes lead to dryness.
- Coal tar-based shampoos also work by slowing down the production of skin cells, but they can sometimes discolor lighter-colored hair.
For best results, it is important to follow the product’s directions, which often recommend leaving the shampoo on the scalp for several minutes before rinsing. If a particular shampoo seems to lose its effectiveness over time, rotating between different types with different active ingredients can be beneficial. The frequency of shampooing is also a factor, as more frequent washing may be needed to manage oil and prevent skin cell buildup. While home remedies like tea tree oil are sometimes used, their effectiveness is not universally proven and they can cause skin irritation. A patch test is recommended before applying such remedies.
When to See a Doctor for Dandruff
While most cases of dandruff can be managed with OTC products, certain situations warrant a visit to a doctor or dermatologist. You should seek medical advice if:
- The itching is intense and begins to interfere with daily activities or sleep.
- Symptoms persist without improvement after several weeks of consistent use of dandruff shampoos.
- The scalp becomes very red, swollen, or painful to the touch.
- The flaking and scaling spread from the scalp to the face or other parts of the body.
These symptoms could indicate a more severe case of seborrheic dermatitis or another underlying skin condition like psoriasis or eczema. A physician can confirm the diagnosis and rule out other potential causes for the symptoms. For persistent or severe cases, a doctor can prescribe stronger treatments not available over the counter, such as prescription-strength shampoos, lotions, foams, or oral medications.