Summer Scalp Issues: Dermatologist Warns of Dandruff, Hair Loss from Sun Exposure

Summer's intense sun can cause more than just sunburn on the face and body; it can also significantly impact scalp health, leading to increased dandruff, dryness, itchiness, and even hair loss. Dr. Ke Bo-huan, a dermatologist with the CDC hair transplant medical team, explains that the primary culprit is often direct UV radiation on the scalp, not necessarily shampoo or diet.

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If the scalp is not protected when going out, skin aging, follicle atrophy, and pigment cell damage caused by ultraviolet rays are actually happening silently.

Dr. Ke notes that unprotected scalps are vulnerable to sunburn, particularly along the hairline, partings, and crown. UVB rays can burn the scalp's surface cells, and repeated sunburns damage the skin barrier, making it more sensitive. This damage can cause the scalp to become dry and dehydrated, leading to accelerated shedding and the appearance of fine, dry dandruff accompanied by persistent itching.

Furthermore, UVA rays penetrate deeper, affecting the blood vessels and connective tissues around hair follicles. Prolonged exposure can cause chronic inflammation and damage to the hair papilla cells. This results in progressively finer hair and increased brittleness, potentially leading to diffuse hair loss over time. Dr. Ke points out that people often forget to protect their scalps, even when applying sunscreen to their face and body.

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When the healthy sebum film is damaged by UV, the scalp will begin to dry and lose water, and metabolism will accelerate, resulting in a large amount of fine, dry dandruff, accompanied by persistent dryness and itching.

To prevent these issues, Dr. Ke recommends three key steps. First, use scalp sunscreens containing SPF, focusing on areas like the hairline and partings. Second, opt for physical barriers like wide-brimmed hats or UV-protective headscarves, especially for those with thinner hair. Finally, avoid prolonged outdoor exposure between 10 a.m. and 2 p.m., when the sun's UV rays are strongest.

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Long-term repeated exposure will cause chronic inflammation of the hair follicles and damage to the hair papilla cells, resulting in finer and finer hair roots and increasingly brittle hair quality, and in severe cases, diffuse hair loss.