Trichoscopy: How Dermatologists Diagnose Hair Loss

Sitting down in a consultation with a bag of fallen hair collected from the shower drain is more common than you might think, and it rarely produces the answer people hope for. Counting shed hairs says something about quantity. It says very little about the cause.

The instrument that does answer the question is unremarkable to look at: a handheld magnifier with a light source, held against the scalp. Trichoscopy, which is dermoscopy applied to hair and scalp, is how a specialist decides what is actually happening before any hair loss treatment is discussed, and the distinction it draws changes the plan entirely.

What the examination adds

Trichoscopy allows the scalp surface, the follicular openings and individual hair shafts to be assessed at magnification without cutting anything. Pattern analysis across those features supports a confident diagnosis and reduces the need for invasive procedures. However scalp biopsy for histological examination remains the gold standard, but its invasiveness limits routine use¹.

For a patient the practical benefit is speed and specificity. Several conditions cause thinning, they look similar to an untrained eye, and treating the wrong one leads to delayed appropriate treatment and wasted months.

Androgenetic alopecia: variability is the signature

Pattern hair loss does not thin the scalp evenly. Affected follicles miniaturise progressively, so thick, medium and fine hairs coexist in the same small area, and that inconsistency is the finding that gives the diagnosis away. A systematic review of 34 studies found hair diameter variability in 94.07% of patients, vellus hairs in 66.45%, and the peripilar sign, a subtle brown halo around the follicular opening, in 43.27%².

Standardised criteria formalise this. The original method paper proposed that more than 10% of hairs in the frontal area falling below 0.03 mm in thickness, together with lower average hair thickness frontally than at the occiput, supports the diagnosis, with shaft thickness heterogeneity above 20% in men and above 10% in women treated as a diagnostic criterion³.

Comparing the front of the scalp against the back is central to that, and it is also why a dermatologist examines several sites instead of only the one area a patient is worried about.

Alopecia areata: dots and broken hairs

A meta-analysis of 39 studies covering 3,204 patients identified the most characteristic findings as yellow dots, black dots, broken hairs, short vellus hairs and tapering hairs, while concluding that no single finding is pathognomonic and diagnosis rests on a constellation of features⁴. In alopecia areata, the immune system attacks hair follicles without destroying them permanently, which is why the follicular openings stay visible and regrowth remains possible.

Scarring alopecia: the openings disappear

This distinction carries the greatest clinical consequence of any in the examination, because it determines whether hair can return at all. In cicatricial or scarring alopecia the follicle is replaced by fibrous tissue, and trichoscopy shows loss of the follicular openings themselves.

A systematic review of 33 articles on lichen planopilaris and frontal fibrosing alopecia reported that early lichen planopilaris shows peripilar cylindrical casts and perifollicular redness with arborising vessels, active frontal fibrosing alopecia shows yellow dots, perifollicular erythema and scattered pigmentation, and inactive disease in both shows a shiny white area, with advanced disease marked by white fibrotic dots and lonely hairs⁵.

Recognising this early carries real consequences. Once follicular openings have gone, treatment aims to arrest further loss instead of recovering what has already been lost, and delay is measured in permanently absent hair. This is the single strongest argument for having thinning assessed properly rather than waiting to see what happens.

Telogen effluvium and the value of looking

Diffuse shedding after illness, surgery, childbirth, weight loss or significant stress typically shows preserved hair diameter with normal follicular openings, which is reassuring precisely because the miniaturisation of pattern loss is absent. The distinction is not always clean, and the two can coexist, which is one reason a single examination sometimes leads to a review appointment instead of an immediate answer.

Why local reference values are needed

Interpretation depends on knowing what normal looks like in the population being examined. Quantitative trichoscopy in 239 healthy Thai adults established normative values, with mean hair density lowest in the temporoparietal area at 133.7 hairs per square centimetre and highest at the vertex at 162.9, mean hair diameter around 80 micrometres across sites, and density declining with age⁶. The authors noted that data for Asian populations has been limited, and that density in Asian groups is relatively lower than in Caucasian and Hispanic groups.

Applying figures derived from a different population risks calling a normal Asian scalp abnormal, or missing genuine thinning in someone who started with a higher baseline.

What to expect at the appointment

The examination itself is quick and painless, and there is nothing to prepare beyond arriving with clean, dry, unstyled hair so the scalp can be seen. Photographs are usually taken at fixed sites so that change can be compared objectively at a later visit, since memory and mirrors are unreliable over months. Blood tests are often requested alongside, because thyroid disease, iron deficiency and other systemic causes influence shedding and cannot be seen on the scalp.

Conclusion

A diagnosis is the part of the process that determines whether anything afterwards can succeed, and it takes a few minutes with the right instrument. Treatments aimed at the wrong condition are not merely ineffective, since the months spent on them are months the correct treatment was not given.

At Angeline Yong Dermatology, Dr Angeline Yong examines the scalp under magnification, compares affected and unaffected sites, and investigates contributing medical causes before advising on any plan, with medical and surgical options available at the clinic. Book a consultation to find out what is behind your shedding before deciding what to do about it.

References

Katoulis, A. C., Pappa, G., Sgouros, D., Markou, E., Kanelleas, A., Bozi, E., Ioannides, D., & Rudnicka, L. (2025). A three-step diagnostic algorithm for alopecia: Pattern analysis in trichoscopy. Journal of Clinical Medicine, 14(4), 1195. https://doi.org/10.3390/jcm14041195

Kuczara, A., Wąskiel-Burnat, A., Rakowska, A., Olszewska, M., & Rudnicka, L. (2024). Trichoscopy of androgenetic alopecia: A systematic review. Journal of Clinical Medicine, 13(7), 1962. https://doi.org/10.3390/jcm13071962

Rakowska, A., Slowinska, M., Kowalska-Oledzka, E., Olszewska, M., & Rudnicka, L. (2009). Dermoscopy in female androgenic alopecia: Method standardization and diagnostic criteria. International Journal of Trichology, 1(2), 123. https://doi.org/10.4103/0974-7753.58555

Al-Dhubaibi, M. S., Alsenaid, A., Alhetheli, G., & Abd Elneam, A. I. (2023). Trichoscopy pattern in alopecia areata: A systematic review and meta-analysis. Skin Research and Technology, 29(6), e13378. https://doi.org/10.1111/srt.13378

Gowda, S. K., Errichetti, E., Behera, B., & Thakur, V. (2025). Trichoscopic features of lichen planopilaris versus frontal fibrosing alopecia: A systematic review. Dermatology Practical & Conceptual, 15(1), 4481. https://doi.org/10.5826/dpc.1501a4481

Leerunyakul, K., & Suchonwanit, P. (2020). Evaluation of hair density and hair diameter in the adult Thai population using quantitative trichoscopic analysis. BioMed Research International, 2020(1), 2476890. https://doi.org/10.1155/2020/2476890

Use of this website signifies your agreement to The Terms of Use & Privacy Policy

Terms of Use

You are deemed to have entered into an agreement with Angeline Yong Dermatology and to have agreed to be bound by the terms set out below by accessing ayd.com.sg (“the Sites”) or by otherwise accessing any content found on this web site. By accessing or using the Site, you acknowledge that you have read, understood, and agreed, without limitation or qualification, to be bound by these Terms & Conditions. The Site is owned and operated by Angeline Yong Dermatology.

Intellectual Property Protection
Use of Angeline Yong Dermatology Content
Changes to the Site
Privacy Policy
No Warranty, Disclaimer of Liability and Indemnity
Force Majeure
Miscellaneous
Governing Law and Jurisdiction

Intellectual Property Protection

The contents and design of the Site and any material e-mailed to you or otherwise supplied to you in conjunction with the Site (such contents, design and materials being collectively referred to as the “Angeline Yong Dermatology Content”, are copyright of Angeline Yong Dermatology. You may not use or reproduce or allow anyone to use or reproduce any trademarks (such as ” Angeline Yong Dermatology” name and logo or other trade names appearing on the Site) for any reason without written permission from Angeline Yong Dermatology. The software, which operates the Site, is proprietary software and you may not use it except as expressly allowed under these Terms. You may not copy, modify, reverse engineer or otherwise interfere with the software.

Use of Angeline Yong Dermatology Content

You may retrieve and display the Angeline Yong Dermatology Content on a computer screen or mobile telephone, print individual pages on paper (but not photocopy them) and store such pages in electronic form for your personal, non-commercial use. You may not save or post any of the Content on blogs, Facebook, and other websites that allows viewing by the general public without written permission from Angeline Yong Dermatology. Except as expressly set out above, you may not reproduce, modify or in any way commercially exploit any of the Angeline Yong Dermatology Content.

Changes to the Site

Angeline Yong Dermatology reserves the right to change, modify, suspend, add or remove portions of the Angeline Yong Dermatology Content available on the Site at any time and to restrict the use and accessibility of the Site in its discretion and without prior notification.

Privacy Policy

The information that you provide about yourself and your company to Angeline Yong Dermatology will only be used in accordance with Angeline Yong Dermatology’s Privacy Policy Statement. We will:

retain your information only for as long as there is a business need
take reasonable steps to ensure that the information is accurate, adequate, relevant and up to date.
update or correct your information held by us whenever necessary
take appropriate measures to prevent and minimize risks of unauthorised access to the information

We may use your personal information, such as your name and contact details, for the following purposes:

to perform the services that you have requested, which may involve contacting you by telephone, mobile phone, fax machine, post or email, including sending you electronic direct mailers.
to allow us to promote our products, events and activities.

No Warranty, Disclaimer of Liability and Indemnity

Whilst every effort has been made to ensure the high quality and accuracy of the Site, Angeline Yong Dermatology makes no warranty, express or implied, concerning the Angeline Yong Dermatology Content, the Site, software or products or services available through the Site (the “Site Services”), which are provided “as is”. Angeline Yong Dermatology expressly disclaims all warranties, including but not limited to warranties of fitness for a particular purpose and warranties of merchantability. In no event will Angeline Yong Dermatology, its affiliates or other suppliers be liable for direct, special, incidental, or consequential damages (including, without limitation, damages for loss of business profits, business interruption, loss of business information or other pecuniary loss) arising directly or indirectly from the use of (or failure to use) or reliance on the Site Services, even if Angeline Yong Dermatology and its affiliates has been advised of the possibility that such damages may arise.

Angeline Yong Dermatology does not guarantee the accuracy, content, or timeliness of the Site Services or that they or related systems are free from viruses or other contaminating or destructive properties. Angeline Yong Dermatology accepts no responsibility for the content on any site to which a hypertext link from this site exists. The links are provided “as is” with no warranty, express or implied for the information provided within them.

Upon accessing to this Site, you agree to indemnify and hold harmless Angeline Yong Dermatology and its affiliates from any claims and expenses, including reasonable legal fees, related to any breach of these Terms by you or your use of any Site Services.

Force Majeure

Angeline Yong Dermatology and its affiliates will not be liable or deemed to be in default for any delay or failure in performance or interruption of the delivery of the Angeline Yong Dermatology Content resulting directly or indirectly from any cause or circumstance beyond its or their reasonable control, including but not limited to failure of electronic or mechanical equipment or communication lines, telephone or other interconnect problems, computer viruses, unauthorized access, theft, operator errors, severe weather, earthquakes or natural disasters, strikes or other labour problems, wars, or government restrictions.

Miscellaneous

Changes to these Terms. Angeline Yong Dermatology may, in its discretion, change these Terms (including those relating to your use of Site and/or the Angeline Yong Dermatology Content. When Terms are changed, Angeline Yong Dermatology will notify you by email or by publishing details of those changes by including them in these Terms. If you use the Site after Angeline Yong Dermatology has published or notified you of the changes, you are agreeing now to be bound by those changes. If you do not agree to be bound by those changes, you should not use the Site any further after they are published. Access to certain areas of the Angeline Yong Dermatology Content may be subject to additional terms and conditions.

Advertising, Third Party Content and other Web Sites. Parts of the Site may contain advertising or other third-party content. Advertisers and other content providers are responsible for ensuring that material submitted for inclusion on the Site complies with international and national law. Angeline Yong Dermatology is not responsible for any third-party content or error, omission or inaccuracy in any advertising material. The Site may contain links to other web sites. Angeline Yong Dermatology is not responsible for the availability of these web sites or their contents.

Assignment of Agreement. This agreement is personal to you and your rights and obligations under these Terms may not be assigned, sub-licensed or otherwise transferred. This agreement may be assigned to a third party by Angeline Yong Dermatology and its affiliates.

Non-Waiver. No delay or omission on the part of either party in requiring performance by the other party of its obligations will operate as a waiver of any right.

Notices. Notices to Angeline Yong Dermatology and its affiliates must be given in writing by letter.

Severability/Survival/Statute of Limitations. If any provision of these Terms is invalid or unenforceable, such will not render all the Terms unenforceable or invalid but rather the Terms will be read and construed as if the invalid or unenforceable provision(s) are not contained therein. Any cause of action of yours with respect to these Terms must be filed in a court of competent jurisdiction in Singapore, within one year after the cause of action has arisen, or such cause will be barred, invalid, and void.

Whole Agreement. Save as expressly referred to herein, any representation, warranty, term or condition not expressly set out in these Terms shall not apply.

Headings. Headings in these Terms are for convenience only and have no legal meaning or effect.

Governing Law and Jurisdiction

These Terms shall be governed by, and construed in accordance with the Laws of the Republic of Singapore. The parties irrevocably agree that the courts of Singapore shall (subject to the paragraph below) have exclusive jurisdiction to settle any dispute which may arise out of, under, or in connection with these Terms or the legal relationship established by them, and for those purposes irrevocably submit all disputes to the jurisdiction of Singapore courts. For the exclusive benefit of Angeline Yong Dermatology and its affiliates, Angeline Yong Dermatology and its affiliates shall retain the right to bring proceedings as to the substance of the matter in the courts of the country of your residence or, where these Terms are entered into in the course of your trade or profession, the country of your principal place of business.

Media.

Trichoscopy: How Dermatologists Diagnose Hair Loss