The scalp is the “soil” for hair growth.
Hair follicles are rooted in the scalp, and the health of the scalp directly affects whether the follicles can function properly.
When the scalp environment is compromised, the blood supply, nutrition, and metabolism of the hair follicles are disrupted, which may trigger or worsen hair loss.
The scalp consists of the epidermis, dermis, and subcutaneous tissue, with a large number of sebaceous glands and sweat glands distributed throughout.
The oil secreted by the sebaceous glands protects the scalp, but either excessive or insufficient secretion can lead to problems.
Excess oil easily attracts dust, promotes microbial growth, and causes inflammation; insufficient oil results in a dry scalp and a damaged barrier.
Inflammation is a common manifestation of an unhealthy scalp and a significant driver of hair loss.
Seborrheic dermatitis is one of the most common scalp inflammations, presenting as erythema, greasy scales, and itching.
Studies have found that the number of *Malassezia* (a yeast-like fungus) in the scalp of patients with seborrheic dermatitis is significantly elevated.
Fatty acids produced by *Malassezia* metabolism irritate the scalp, triggering an inflammatory response that disrupts the hair follicle cycle, leading to increased telogen effluvium.
In addition to seborrheic dermatitis, other inflammatory skin conditions such as psoriasis and contact dermatitis can also attack hair follicles by releasing inflammatory cytokines.
These inflammatory cytokines cause hair follicles to prematurely enter the telogen or catagen phase, resulting in significant hair shedding over a short period.
It should be emphasized that this type of hair loss is usually reversible; once inflammation is controlled, hair can regrow.
The microbial community on the scalp also plays a key role.
A healthy scalp is primarily colonized by *Propionibacterium* and *Staphylococcus* species, maintaining a dynamic balance.
When the microbial balance is disrupted (e.g., overgrowth of *Malassezia*), it damages the scalp barrier and triggers an immune response.
This immune response not only causes dandruff and itching but may also attack immune cells around the hair follicles, affecting normal hair follicle growth.
Androgenetic alopecia is the most common type of hair loss and is linked to genetics and androgen levels.
However, recent studies indicate that scalp microinflammation also plays a contributory role in androgenetic alopecia.
The scalp of patients with androgenetic alopecia often exhibits mild inflammation, which may stem from microbial metabolites or oxidative stress around the hair follicles.
Inflammation exacerbates the process of follicular miniaturization, causing hair to gradually become thinner, shorter, and eventually shed.
Telogen effluvium is another common form of diffuse hair loss, typically triggered by stress, illness, malnutrition, or medications.
Poor scalp health—such as prolonged lack of cleansing or excessive cleansing—weakens the tolerance of hair follicles, making them more prone to entering the telogen phase.
Improving scalp care can help prevent and alleviate telogen effluvium to some extent, but it cannot replace etiological treatment.
Alopecia areata is an autoimmune form of hair loss characterized by well-defined, round patches of hair loss.
The local immune system in the scalp attacks hair follicles, causing them to abruptly enter the telogen phase.
Although the exact cause of alopecia areata is not fully understood, scalp infection or inflammation may act as a trigger.
Controlling scalp inflammation helps reduce the risk of recurrence in alopecia areata, but it is not the primary treatment.
So, how can we maintain scalp health to prevent hair loss?
First, cleanse gently. Choose a mildly acidic shampoo with a pH close to that of the scalp, and avoid frequent use of strongly alkaline or overly degreasing products.
When washing hair, massage the scalp gently with your fingertips—do not scratch with your nails, as this may damage the scalp barrier.
Second, maintain adequate moisture. For a dry scalp, use moisturizing conditioner in moderation, but avoid leaving excessive product residue on the scalp.
Third, avoid wearing tight hats or hair accessories for prolonged periods to reduce physical traction.
Fourth, maintain a balanced diet. Deficiencies in iron, zinc, vitamin D, and B vitamins can affect hair follicle health, but a balanced diet is sufficient—there is no need for indiscriminate supplementation.
Fifth, manage stress. Chronic mental tension can affect scalp microcirculation and immune status through neuroendocrine pathways.
It is particularly important to note that the relationship between scalp health and hair loss is bidirectional:
Scalp problems can cause hair loss, and hair loss itself (e.g., androgenetic alopecia) can alter the scalp microenvironment, creating a vicious cycle.
Therefore, improving scalp care is one component of comprehensive hair loss management, but it cannot address all types of hair loss.
If persistent heavy hair loss (more than 100 hairs per day) or significant scalp redness, swelling, pain, or pustules occur, seek medical attention promptly.
A dermatologist will make a definitive diagnosis through history taking, scalp examination, and tools such as trichoscopy, and will develop a targeted treatment plan.
Using over-the-counter hair growth products or folk remedies without guidance may delay treatment or even worsen scalp issues.
In summary, scalp health is the foundation for robust hair growth, but the causes of hair loss are complex and varied.
Maintaining a healthy scalp helps reduce inflammation-related hair loss; however, for hair loss dominated by genetic factors, formal medical treatment remains essential.
(For reference only and does not constitute medical advice.)