Types of hair loss and how they differ

Hair loss treatments act on specific causes. Finasteride lowers the hormone that shrinks follicles in pattern hair loss, but it does nothing for alopecia areata, which is an immune condition. Shedding after a high fever usually settles by itself. Scarring alopecia needs early treatment of the inflammation, because a follicle that has been destroyed cannot grow hair again.

Pattern hair loss is the most common type in both men and women. The European S3 guideline notes that it affects up to 80% of white men and 42% of women over a lifetime^[1]. Rates are lower in Korea: in a survey of 10,132 Koreans, 14.1% of men and 5.6% of women had pattern hair loss, rising to 46.9% of men and 24.7% of women over 70^[2].

The same survey found that Korean men more often keep their front hairline and thin on top in a “female pattern” than white men do^[2]. For this reason the Asian consensus guideline uses the BASP (basic and specific) classification, which was designed to describe patterns that are more frequent in Asian patients^[3]. In pattern hair loss, follicles shrink step by step. Under magnification the doctor sees hairs of very different thickness, many thin hairs and more openings that carry only one hair^[4]. Women usually keep their front hairline; see female pattern hair loss for how it differs.

Losing 50 to 100 hairs a day is normal, according to both the NHS hair loss page and the American Academy of Dermatology (both checked 2026-10-18), but a daily count alone does not diagnose anything. In telogen effluvium, a trigger such as illness or physiological stress pushes many growing hairs early into the resting (telogen) phase^[5], and they then shed together all over the scalp. The AAD lists high fever, an operation, giving birth, losing 20 pounds (about 9 kg) or more, intense stress and stopping birth-control pills as common triggers. Most people notice the shedding a few months after the event. In acute cases, hair tends to regain its normal fullness within six to nine months.

A review of the condition describes a high rate of remission but no treatment aimed at the cause itself, so care focuses on finding and removing the trigger^[6]. Shedding can also reveal pattern hair loss that was already developing, and some shedding persists or recurs. Shedding also changes with the seasons, with more hairs shed in late summer and autumn^[7][8]; see autumn hair shedding.

Alopecia areata causes round, smooth patches where the immune system has attacked the follicles. It can also affect the eyebrows, eyelashes and beard. Under magnification, black dots and short “exclamation mark” hairs suggest that the disease is active^[4].

Treatment follows its own guidelines. The 2026 S3 guideline from German and Austrian dermatology societies gives topical corticosteroids the only high-level recommendation among treatments applied to the skin. Among whole-body treatments, only systemic corticosteroids and JAK inhibitor tablets have high-level recommendations, and only for adults. It also advises that every patient hears about wigs and other cosmetic options^[9].

Traction alopecia comes from long-term pulling: tight ponytails, buns, braids, extensions or headwear. It often recovers when the pulling stops early, so a change of hairstyle is part of the treatment.

Scarring alopecias, such as lichen planopilaris and frontal fibrosing alopecia, destroy follicles through inflammation. They may itch, burn or feel tender. Under magnification, the affected skin shows milky-red or ivory-white areas without follicle openings^[4]. A scalp biopsy is often needed to confirm the diagnosis, and early treatment protects the hair that remains.

• Iron deficiency and thyroid disease, which a blood test can check. The NHS lists iron deficiency among the causes of temporary hair loss.
• Hair breakage from bleaching, perms or heat styling. It looks like thinning, but the roots are healthy.
• Scalp conditions such as fungal infection or severe dandruff, which change how the scalp looks under magnification.
• Repeated hair pulling or twisting, which leaves broken hairs of different lengths.