If your scalp keeps itching even after you have washed and thoroughly dried your hair, the cause may be more than simple dryness.
According to medical institutions including Asan Medical Center and Seoul National University Hospital on the 24th, one of the leading causes of such symptoms is seborrheic dermatitis, a very common chronic inflammatory condition that affects 3% to 5% of adults. It occurs most frequently within the first three months of life and between the ages of 40 and 70, and is also common among adolescents and men in their 30s and 40s.
The Scalp Is Where It Appears First and Most Often
Seborrheic dermatitis can develop anywhere the skin produces a lot of sebum, including the face, chest and armpits, but the scalp is considered the site where symptoms appear earliest and most commonly.
On the scalp, it produces flaking of the skin resembling rice bran — commonly known as dandruff — and in severe cases the scalp turns red with yellowish scales and crusts. Unlike simple dryness, the hair may become greasy or develop a strong odor by the afternoon, a sign that warrants suspicion of seborrheic scalp dermatitis.
The exact cause of seborrheic dermatitis is not yet clearly understood. It is believed to result from a combination of several factors. The most likely candidate is Malassezia, a fungus naturally present on the skin. The fungus itself is not malignant and is a normal resident microbe found in everyone, but it can multiply rapidly and trigger an inflammatory response when sebum production becomes excessive or the scalp environment changes.
Sebaceous gland activity is also involved. This is supported by the fact that seborrheic dermatitis occurs mainly in adulthood, when sebaceous glands are active. Genetic factors, family history, hormonal changes, stress, lack of sleep and frequent drinking are also cited as factors that worsen symptoms. Seasonally, symptoms tend to worsen in the low temperatures and dry indoor conditions of autumn and winter, and in summer as sweat and ultraviolet exposure increase.
Scalp dryness or frequent washing can also be a cause. Frequent use of shampoos with strong cleansing power strips away too much of the scalp's natural oils, which can actually worsen dryness and irritation, while failing to rinse out shampoo or conditioner thoroughly can leave residue that irritates the scalp and causes itching.
Mild Shampoo, Lukewarm Water — Lifestyle Management Comes First
Experts recommend management methods that can be grouped into four main categories.
First, use a mild shampoo that is gentle on the scalp, and avoid washing your hair too frequently. When washing, use lukewarm water rather than hot water, and rinse out shampoo and conditioner thoroughly so that no residue remains.
Care is also needed when drying your hair. Because the hot air from a dryer can overheat the scalp and worsen itching, it is better to let hair dry naturally or use lukewarm air when possible.
If symptoms are not severe, antifungal shampoos containing ketoconazole, selenium sulfide or zinc pyrithione may help. However, if symptoms do not improve or keep recurring even with these products, self-care alone has its limits.
Lifestyle management is also important. Stress and fatigue can increase cortisol secretion, which promotes sebum production and can upset the balance of scalp microbes. Adequate sleep, a regular routine and moderate drinking provide real benefits.
Finally, if the itching is severe or accompanied by yellow dandruff, a red scalp and greasy scales, and the symptoms persist for several weeks or more, it is likely seborrheic dermatitis rather than simple dryness. In that case, it is safer to see a dermatologist to identify the exact cause and receive appropriate treatment, such as antifungal medication or topical steroids, rather than relying on self-treatment.
