In short. A dermatologist's assessment of hair loss is a structured history, examination, trichoscopy and targeted testing rather than a single test. It exists to establish which category of hair loss is present, whether the follicle is still alive, and whether scarring or another condition is the real problem before any treatment is chosen.
Key points
- Hair loss is a symptom rather than a diagnosis, and the same shedding has different causes.
- Pattern and speed of loss matter more than the amount being shed.
- Trichoscopy is the single most useful test in a hair clinic.
- Blood tests are targeted rather than routine, and biopsy is reserved for specific cases.
- Lost follicular openings with scaling and redness point towards scarring alopecia.
What is the assessment trying to establish?
Hair loss is a symptom rather than a diagnosis, and the same amount of shedding can have completely different causes. The assessment exists to answer three questions: which category of hair loss is this, is the follicle still alive, and is anything else going on that needs treating. Every later decision depends on those answers.
What does the history reveal?
The pattern and the speed of loss matter more than the amount. Loss that came in over years across the crown suggests pattern hair loss. Loss that appeared over weeks, two to three months after an illness, childbirth, an operation, a crash diet or a period of severe stress, suggests a shedding condition. Patches that appeared suddenly suggest an immune cause. We ask about scalp itching, burning, tenderness or scaling; about styling habits, relaxers, dyes and heat; about iron, thyroid and autoimmune disease; about every medicine and supplement being taken; and about family history on both sides. In women we ask specifically about menstrual irregularity, oily skin, unwanted facial or body hair, and recent pregnancy or menopause, because those answers change the tests we order.
Examination and the pull test
Examination maps where hair is thin and where it is dense, and whether the frontal hairline is preserved or receding. A simple pull test, drawing a bundle of about fifty to sixty hairs firmly but gently from several sites, shows how many hairs are in the shedding phase at that moment. Part-width measurement and standardised photography record a baseline against which future change can be judged.
What does trichoscopy add?
Trichoscopy is dermoscopy of the scalp, and it is the single most useful test in a hair clinic. Under magnification we look at whether follicles are still opening onto the surface, whether hair shafts vary in diameter, and whether there is perifollicular scaling, redness or loss of openings. Variation in shaft diameter supports pattern hair loss. A preserved follicular opening supports a non-scarring process. Lost openings, perifollicular scale and redness point towards scarring alopecia, which is a different and more urgent problem. It is quick, painless, and often removes the need for a biopsy, or tells us precisely where a biopsy should be taken from.
How do the tests fit together?
| Step | What it examines | What it can show | When it is used |
|---|---|---|---|
| History | Pattern and speed of loss, triggers, medicines, family history | Which category of loss is likely, and which tests to order | At the first consultation |
| Examination and pull test | Density, hairline, hairs in the shedding phase | How active shedding is at that moment | Clinical examination |
| Part-width measurement and photography | A recorded baseline | Future change judged against it | At baseline and follow-up |
| Trichoscopy | Follicular openings, shaft diameter, perifollicular skin | Pattern loss, a non-scarring process, or scarring alopecia | Before deciding on a biopsy |
| Blood tests | Thyroid function, iron stores, vitamin D, hormones in selected women | A contributing condition | When the history or examination suggests one |
| Scalp biopsy | Tissue in active, untreated disease | Scarring alopecia or an unclear diagnosis | Suspected scarring, unclear diagnosis, poor response |
Blood tests and biopsy
Blood tests are not routine for every patient. They are worthwhile when the history or the examination suggests a contributing condition: thyroid function, iron stores, vitamin D, and in women a hormone panel when cycles are irregular or there are signs of excess androgens. A scalp biopsy is reserved for cases where scarring alopecia is suspected, where the diagnosis remains unclear, or where the response to treatment is unexpectedly poor. Biopsy is most informative in active, untreated disease, which is why it should not be delayed once scarring is a serious possibility.
When should you ask for an assessment?
- Hair loss that comes with scalp pain, burning, itching, scaling, or visible redness.
- In a woman, thinning plus irregular periods, oily skin, or unwanted facial hair growth.
- Hair loss while taking a regular medicine, or after childbirth, surgery or severe illness.
Sources
Internal links
Frequently asked questions
What does trichoscopy tell the dermatologist?
Whether follicles are still opening onto the surface, whether hair shafts vary in diameter, and whether there is perifollicular scaling or redness. It shows whether the follicle is alive, whether the process is scarring, and whether shedding is active.
Are blood tests always needed for hair loss?
No. Testing is targeted rather than routine. Thyroid function, iron stores, vitamin D and, in selected women, a hormone panel are worthwhile when the history or examination suggests a contributing condition, such as irregular cycles or signs of excess androgens.
When is a scalp biopsy needed?
It is reserved for suspected scarring alopecia, an unclear diagnosis, or an unexpectedly poor response to treatment. Biopsy is most informative in active, untreated disease, which is why it should not be delayed once scarring is a serious possibility.
Risks & Limitations
- Most hair loss is progressive and managed rather than reversed; treatment holds the line more often than it restores it.
- Treatment takes 6–12 months before a response can be judged fairly, and must usually be continued indefinitely to keep the result.
- Stopping treatment commonly means losing the hair that was regained, usually within months.
- Some oral agents cause sexual, mood and metabolic side effects, and several require blood monitoring, blood-pressure monitoring, or pregnancy prevention.
- Hair transplantation moves existing hair; it does not create new hair and does not stop the underlying process.
- Scarring alopecia destroys the follicle permanently, so hair lost before treatment begins cannot be recovered.
- No treatment works for everyone, and response cannot be predicted with certainty.
When to Seek Care
- Sudden patchy hair loss, especially with scalp redness, scaling, itching or pain.
- Hair loss with fever, joint pain, mouth ulcers, or a rash elsewhere on the body.
- Scarring changes: an area of scalp that has become smooth, shiny or pale, with loss of the follicular openings.
- Eyebrow or eyelash loss, which suggests a more extensive or systemic process.
- Hair loss with fatigue, palpitations, weight change, or heavy or irregular periods — a systemic cause needs excluding.
References & Further Reading
- American Academy of Dermatology (AAD) — public and clinical guidance on hair and scalp disorders
- Chinese Medical Association, Dermatology Branch — clinical guidance
- Cochrane Library — systematic reviews in dermatology
- World Health Organization (WHO) — general health and nutrition resources
This page is patient education, not medical advice, and it does not cite individual studies. Discuss your own case with a qualified clinician. To arrange an assessment at Chongqing West District Hospital, see Contact & Consultation.