Abstract
Objectives
To establish accurate and objective dermoscopic diagnostic criteria and grading standards for males and females with androgenetic alopecia (AGA).
Methods
Twenty patients each with AGA, diffuse alopecia areata, telogen effluvium, and healthy controls were enrolled in the current study. In addition, 60 patients with grades F1/V1, F2/V2, and F3/V3 AGA (20 cases each) were enrolled. The patients underwent dermoscopic examinations. The sensitivity and specificity of the diagnostic criteria were based on the 60 AGA and 60 non‐AGA. In addition, 150 patients diagnosed with AGA clinically and by dermoscopy were enrolled to calculate the accuracy of the grading criteria.
Results
The diagnostic criteria included primary, secondary, and exclusion criteria. The grading criteria included three indices, which divided the severity of AGA into grades 1, 2, and 3. The sensitivity and specificity of the diagnostic criteria were 98.3% and 96.7% respectively. The accuracy of grade 1, 2, and 3 dermoscopic grading criteria were 96%, 92%, and 100% respectively, with a total accuracy of 96%.
Limitations
To test the diagnostic and grading criteria, more patients need to be collected.
Conclusions
The dermoscopic diagnostic and grading criteria are objective with good accuracy, which could provide a reasonable basis for the early diagnosis, grading treatment, and improved prognosis for AGA.
Keywords: androgenetic alopecia, criteria, dermoscopy, diagnosis, grade
1. INTRODUCTION
AGA is an androgen‐related disorder that affects both men and women. 1 AGA is characterized by progressive thinning of hair diameter and decreased hair density according to 2011 Guidelines on AGA. 2 The early clinical manifestation of AGA involves the forehead and frontal hairline bilaterally with progressive hair loss on the vertex scalp. 3 AGA should be differentiated clinically from diffuse alopecia areata and telogen effluvium. Norwood 4 divided male AGA into 7 grades and 12 types and Ludwig 5 divided female AGA into 3 grades according to the severity of hair loss; however, both of these classification methods have limitations. Norwood classification is complicated and inconvenient to use in clinical practice, and only applies to men. Ludwig classification applies to women only. In 2007 Lee 6 proposed a new general classification method (BASP [BA, basic; and SP, specific]) that is applicable to men and women. 7 BASP classification is suitable for clinical use and is recommended by multiple guidelines as a clinical classification method for AGA. The severity classification of AGA can provide a basis for clinicians to judge the treatment plan and prognosis of the disease. AGA clinical diagnosis and classification criteria, however, are mainly based on doctor's experience, which is always subjective.
The scalp and hair shaft of AGA have specific characteristics under dermoscopy. 8 The only dermoscopic diagnostic criteria for female AGA currently in use were proposed by Lacharriere 9 in 2001 with 98% specificity. The suitability for male AGA has not been confirmed. Moreover, the diagnostic criteria do not quantify the other indicators except proportion of thin hairs. In addition to AGA, yellow dots are more common alopecia areata. And, it lack exclusion criteria. Besides, the indicators that have characteristic diagnostic value for AGA under dermoscopy, such as the white spots, were not included. Rakowska proposed more simplified diagnostic criteria. 10 The simplified diagnostic criteria quantifies hair shaft thickness heterogeneity and proportion of single hair follicle units, but specificity and sensitivity have not been established. In addition, there are no dermoscopic grading criteria by which to determine the severity of AGA.
Therefore, there is a need to analyze the relevant dermoscopic findings to create new criteria for AGA.
2. DATA AND METHODS
2.1. Patients and dermoscopic examinations
All patients and healthy controls were admitted to Dermatology Alopecia Clinic of the First Affiliated Hospital of Soochow University between December 2020 and January 2023. The male‐to‐female ratio of each group was 1:1 independent of age. Diagnoses were made by two experienced clinicians and dermatoscopy was performed by one technician. Dermatoscopic findings and related indicators were recorded by two dermatoscopic diagnosticians. The dermatoscopic sites in patients included the most apparent hair loss on the frontal and/or vertex areas and external occipital protuberance. The points of the scalp for capturing dermatoscope images are represented by F and V. The dermatoscopic sites in healthy controls were the midpoint of two ears on the apex of the head and external occipital protuberance. 11 Dermoscope used was a CBS Trichoscope system (Bose Electronic Co, Wuhan, Hubei, China) with a magnification of 50x and a shooting area of approximately 45.7 mm2. Patients were advised not to wash their hair for 2–3 days prior to the examination and the was examined using a non‐contact trichoscope. The definitions of hair types were as follows: rough hairs, diameter ≥ 0.06 mm; intermediate hairs = 0.03–0.06 mm; thin hairs < 0.03 mm; vellus hairs < 0.03 mm and length < 2–3 mm. Hair shaft thickness heterogeneity refers to proportion of hairs < 0.06 mm (including intermediate, thin, and vellus hairs) ≥20%.
CAPSULE SUMMARY
This study proposed the dermoscopic diagnostic and grading criteria for androgenetic alopecia (AGA), which have wide application and high efficiency.
The dermoscopic diagnostic criteria and grading standards can facilitate the diagnosis of AGA and for patients with different degrees of AGA severity, the appropriate treatment can be rendered.
2.2. Diagnostic criteria for AGA using dermoscopy
AGA, diffuse alopecia areata, telogen effluvium, and healthy controls were studied (n = 20 each). Dermoscopy was performed and the following dermoscopic findings were recorded. The positive rates for each finding are will be calculated and listed. A positive dermatoscopic finding rate ≥60% in AGA was considered to have diagnostic value. A positive dermoscopic finding rate was 100% in AGA and rarely occurred in other types of alopecia and healthy controls, and was used as primary diagnostic criterion in AGA. A positive dermoscopic finding rate of 0 in AGA and ≥60% in other types of alopecia and healthy controls were considered to have exclusion value.
2.3. Grading criteria for AGA using dermoscopy
AGA with F1 or V1, F2 or V2, or F3 or V3 grades were studied (n = 20 each) according to the BASP classification and the following indicators of hair coverage were measured: proportion of vellus hair; thin hair; intermediate hair on the frontal and/or vertex scalp; proportion of hairs <0.06 mm on the frontal and/or vertex scalp; proportion of hairs <0.03 mm on the frontal and/or vertex scalp; proportion of single hair follicle units on the frontal and/or vertex scalp; and the ratio of rough hairs to the vertex/occipital scalp. The various indices in AGA with different grades were compared, and the indices with significant statistical differences were selected as the dermoscopic grading criteria for AGA severity. The cut‐off value is derived from the median.
2.4. Sensitivity, specificity, and accuracy
Sixty AGA (BASP F1/V1, F2/V2, and F3/V3 [n = 20 patients each]), 20 with diffuse alopecia areata, 20 with telogen effluvium, and 20 healthy controls were studied. Two physicians diagnosed the 120 patients based on dermatoscopic findings using the new dermoscopic diagnostic criteria which this study established. The sensitivity and specificity of the AGA dermoscopic diagnostic criteria were calculated. In addition, 150 AGA diagnosed both clinically and by dermoscopy were classified according to BASP classification (F1/V1, F2/V2, and F3/V3 [n = 50 patients each]). The severity of AGA was graded using the established dermoscopic grading criteria, and the accuracy of the grading criteria was calculated.
2.5. Statistical methods
IBM SPSS Statistics 26 statistical software was used for statistical analysis of the data, and a chi‐square test was used for single factor analysis. A P < 0.05 was considered statistically significant.
3. RESULTS
3.1. Diagnostic and grading criteria for AGA using dermoscopy
In patients with AGA, diffuse alopecia areata, and telogen effluvium, and healthy controls, the visible dermoscopic findings included the following: hair shaft thickness heterogeneity; vellus hairs; single hair follicle units; the brown peripilar sign; yellow dots; white dots; scalp honeycomb pigmentation; black dots; broken hairs; exclamation mark hairs; pigtails hairs; upright regrowing; hairless hair follicles; and invisible hair follicles (Figure 1). The positive rates of findings differed between different types of alopecia and healthy controls (Table 1). Among different severity grades of AGA, there were significant differences in proportion of vellus hairs, thin hairs, intermediate hairs, hairs < 0.06 mm, hairs < 0.03 mm, single hair units, and ratio of rough hairs on the vertex/occipital (Table 2). The median of healthy controls and grade F1/V1: proportion of hairs ＜0.03mm on the frontal/vertex scalp is 20.3%; the ratio of rough hairs to the vertex/occipital scalp is 81.3; and the proportion of single hair follicle units on the frontal/vertex scalp is 31.4%. The median of grade F1/V1 and grade F2/V2: proportion of hairs＜0.03mm on the frontal/vertex scalp is 30.3%; the ratio of rough hairs to the vertex/occipital scalp is 60.0%. The median of grade F2/V2 and grade F3/V3: proportion of hairs＜0.03mm on the frontal/vertex scalp is 54.6%; the ratio of rough hairs to the frontal/vertex scalp is 43%; and the proportion of single hair follicle units on the frontal/vertex scalp is 49.4%. Dermoscopic diagnostic criteria for AGA include primary, secondary, and exclusion criteria; Grading criteria included three indices, which divided the severity of AGA into grades 1, 2, and 3 (Tables 3 and 4; Figure 2).
FIGURE 1.
The visible dermoscopic findings in different types of hair loss and health people. (A) Hair shaft thickness heterogeneity, the proportion of hairs <0.06 mm(including intermediate hairs, thin hairs and vellus hairs) ≥20%. (B) Brown peripilar sign. (C) Yellow dots. (D) Single hair follicle unit. (E) Vellus hairs. (F) White dots. (G) Scalp honeycomb pigmentation. (H) Hairless hair follicles. (I) Invisible hair follicles. (J) Black dots. (K) Broken hairs. (L) Exclamation mark hairs. (M) Pigtails hairs. (N) Upright regrowing. (O) Trichoscopic image on the vertex scalp of a healthy man. (P) Trichoscopic image on the vertex scalp of a healthy woman.
TABLE 1.
The positive rates of the findings seen in dermoscopic examination of different types of hair loss and healthy controls.
| Parameters seen in trichoscopic examination | Healthy people (n = 20) | AGA (n = 20) | Diffuse alopecia areata (n = 20) | Telogen effluvium (n = 20) |
|---|---|---|---|---|
| Hair shaft thickness heterogeneity | 0 | 20 (100%) | 0 | 0 |
| Vellus hairs >10% | 2 (10%) | 16 (80%) | 16 (80%) | 14 (70%) |
| Single hair follicle unit >30% | 0 | 17 (85%) | 18 (90%) | 18 (90%) |
| Brown peripilar sign | 6 (30%) | 14 (70%) | 4(20%) | 4 (20%) |
| Yellow dots | 2 (10%) | 15 (75%) | 16(80%) | 0 |
| White dots | 0 | 5 (25%) | 0 | 0 |
| Scalp honeycomb pigmentation | 0 | 5 (25%) | 0 | 0 |
| Black dots | 0 | 0 | 18 (90%) | 0 |
| Broken hairs | 0 | 0 | 19 (95%) | 0 |
| Exclamation mark hairs | 0 | 0 | 14 (70%) | 0 |
| Pigtails hairs | 0 | 0 | 8 (40%) | 4 (20%) |
| Upright regrowing | 2 (10%) | 0 | 4 (20%) | 18 (90%) |
| Hairless hair follicles | 2 (10%) | 12 (60%) | 20 (100%) | 10 (50%) |
| Invisible hair follicles | 0 | 6 (30%) | 6 (30%) | 0 |
TABLE 2.
Analysis of the differences of dermatoscopic indexes of AGA at all levels.
|
Indexes Group |
Grade F1/V1 (n = 20) |
Grade F2/V2 (n = 20) |
Grade F3/V3 (n = 20) |
Statistical parameters | P |
|---|---|---|---|---|---|
| Proportion of vellus hairs on the frontal and/or vertex scalp(%) | 6.8 ± 2.7 | 14.1 ± 3.6 a | 31.2 ± 17.1 a , b | F = 30.023 | <0.01 |
| Proportion of thin hairs on the frontal and/or vertex scalp(%) | 17.6 ± 3.8 | 22.4 ± 7.1 | 42.4 ± 19.7 a , b | F = 23.124 | <0.01 |
| Proportion of intermediate hairs on the frontal and/or vertex scalp(%) | 11.0 ± 5.4 | 14.7 ± 5.4 a | 10.8 ± 5.4 b | F = 3.320 | 0.043 |
| Proportion of hairs < 0.06 mm on the frontal and/or vertex scalp(%) | 35.4 ± 8.2 | 51.2 ± 6.7 a | 84.4 ± 12.5 a , b | F = 139.962 | <0.01 |
| Proportion of hairs < 0.03 mm on the frontal and/or vertex scalp(%) | 24.4 ± 3.6 | 36.5 ± 7.0 a | 73.6 ± 14.4 a , b | F = 147.053 | <0.01 |
| Proportion of single hair follicle unit on the frontal and/or vertex scalp(%) | 41.2 ± 5.8 | 43.8 ± 5.0 | 80.0 ± 13.4 a , b | F = 118.625 | <0.01 |
| Ratio of the rough hairs on the vertex/occipital sclap (%) | 73.2 ± 7.4 | 52.7 ± 6.2 a | 20.1 ± 15.7 a , b | F = 126.835 | <0.01 |
There is a statistical difference between this group and Grade F1/V1.
There is a statistical difference between this group and Grade F2/V2.
TABLE 3.
Diagnostic criteria for AGA using dermoscopy.
| Criteria | Indexes |
|---|---|
| Primary criteria | Hair shaft thickness heterogeneity on the frontal and/or vertex scalp |
| Secondary criteria | ①Proportion of single hair follicle unit on the frontal and/or vertex scalp ≥30% |
| ②Proportion of vellus hairs on the frontal and/or vertex scalp >10% | |
| ③There are at least two other dermoscopic signs: brown peripilar sign, yellow dots, white dots, scalp honeycomb pigmentation | |
| Exclusion criteria | Black dots, broken hairs, exclamation mark hairs |
Note: AGA can be diagnosed if the primary criteria +≥one of the secondary criteria are met and the exclusion criteria are not met.
TABLE 4.
Grading criteria for AGA using dermoscopy.
| Grade 1 | Grade 2 | Grade 3 | |
|---|---|---|---|
| Proportion of the hairs <0.03 mm on the frontal and/or vertex scalp(%) | 20–30 | 30–50 | >50 |
| Proportion of the single hair follicle unit on the frontal and/or vertex scalp (%) | 30–50 | 30–50 | >50 |
| Ratio of the rough hairs on the vertex/occipital sclap (%) | 60–80 | 40–60 | <40 |
Note: AGA patients can be graded according to ≥ two indexes.
FIGURE 2.
Clinical photographs and dermoscopic images of AGA in men. (A) A healthy man. (B) Grade 1. (C) Grade 2. (D) Grade 3. (E) Grade 3 (Grade U). Clinical photographs and dermoscopic images of AGA in women. A: A healthy woman; B: Grade 1; C: Grade 2; D: Grade 3.
3.2. Sensitivity, specificity, and accuracy
Taking the diagnosis made by clinicians as gold standard, 59 patients with a clinical diagnosis of AGA were diagnosed with AGA by dermoscopy and 1 patient was diagnosed with diffuse alopecia areata by dermoscopy. Among 60 patients who did not have AGA, 2 were diagnosed with AGA by dermoscopy who were clinically diagnosed as healthy. One patient had curly hair and the other patient had more basal hair who looks like a healthy person. The diagnostic sensitivity and specificity of the AGA dermoscopic diagnostic criteria were 98.3% and 96.7%, respectively (Table 5).
TABLE 5.
Sensitivity and specificity of diagnostic criteria.
| Clinical diagnosis | n | Diagnostic criteria for AGA using dermoscopy | |
|---|---|---|---|
| AGA | Non‐AGA | ||
| AGA | 60 | 59 | 1 |
| Non‐AGA | 60 | 2 | 58 |
The BASP classification was used as gold standard for grading AGA severity. Fifty AGA were diagnosed as F1/V1, and 48, 2, and 0 as grades 1, 2, and 3, respectively, by dermoscopy. Fifty AGA were diagnosed as F2/V2, and 46, 1, and 3 as grades 2, 1, and 3, respectively, by dermoscopy. Fifty AGA were diagnosed as F3/V3, and 50, 0, and 0 as grades 3, 1, and 2, respectively, by dermoscopy. The severity of dermoscopic grading was less than the BASP classification in 1 patient and higher than the BASP classification in 5 patients. The accuracy of AGA grades 1, 2, and 3 according to dermoscopic grading criteria were 96%, 92%, and 100% respectively, with a total accuracy of 96% (Table 6).
TABLE 6.
Accuracy of grading criteria.
| BASP | n | Grading criteria for AGA using dermoscopy | ||
|---|---|---|---|---|
| Grade 1 | Grade 2 | Grade 3 | ||
| F1/V1 | 50 | 48 | 2 | 0 |
| F2/V2 | 50 | 1 | 46 | 3 |
| F3/V3 | 50 | 0 | 0 | 50 |
| Total | 150 | 49 | 48 | 53 |
4. DISCUSSION
The current study showed that dermatoscopic signs visible in ≥60% of AGA included hair shaft thickness heterogeneity (100%), proportion of single hair follicle units > 30% (85%), vellus hairs > 10% (80%), yellow dots (75%), the brown peripilar sign (70%), and hairless hair follicles (60%), which were used as indicators for the dermoscopic diagnosis of AGA. Hair shaft thickness heterogeneity was found in all AGA, but not in diffuse alopecia areata, telogen effluvium, and healthy controls. This finding could reflect the gradual thinning and softening process of hair in AGA, which is in agreement with the clinical manifestations of AGA in which the hairs vary in diameter from coarse‐to‐fine. Therefore, hair shaft thickness heterogeneity was used as the primary diagnostic criteria. Healthy controls may have < 10% vellus hairs. Rakowska 10 reported that proportion of vellus hairs on the forehead of female AGA (20.9 ± 12%) is significantly increased compared to healthy controls (6.15 ± 4.6%). In the current study, proportion of vellus hairs > 10% also occurred in a small percentage of healthy controls (10%) and in the majority of diffuse alopecia areata and telogen effluvium (80% and 70%, respectively). A previous studies had calculated that proportion of single hair follicle units in healthy controls is < 35% in the frontal, < 30% in the occipital, and < 40% in the temporal. 12 In the current study, proportion of single hair follicle units on the frontal and/or vertex scalp ≥30% and vellus hairs >10% could be included as secondary criteria. The brown peripilar sign was observed in healthy controls and AGA, but the percentage of AGA was higher. Therefore, the brown peripilar sign can be included as secondary criterion. Yellow dots in AGA are mainly caused by the accumulation of lipids secreted by sebaceous glands in hairless hair follicles. 13 Yellow dots occur in AGA and healthy controls, and proportion can be influenced by washing hairs. proportion of yellow dots observed in AGA has been reported to be 66%, 14 30.5%, 15 10%−26%, 16 and 7%. 17 The incidence of yellow dots in AGA is higher than healthy controls. In the current study yellow dots appeared in 70% of AGA, which was significantly more than healthy controls. Yellow dots could be used as a suggestive sign in the diagnosis of AGA; however, they are more common in alopecia areata. Therefore, yellow dots should not be used as a main criterion. The specificity of hairless hair follicles was not high, and it shouldn't be a diagnostic criterion. White dots and scalp honeycomb pigmentation occur in 25% of AGA, although < 60%, they occur in AGA with high specificity and can be included as secondary criteria. Black dots, broken hairs, and exclamation mark hairs were observed in diffuse alopecia areata (proportion ≥ 60%), but not AGA, telogen effluvium, or healthy controls. Therefore, they can be used to identify AGA and diffuse alopecia areata, and included as exclusion criteria. Upright regrowing (proportion ≥ 60%) was observed in telogen effluvium and diffuse alopecia areata, as well as healthy controls, but not AGA. Because of the low specificity, it was not an exclusion criterion.
The diagnostic criteria are suitable for both men and women. The new criteria adds a differential diagnosis to improve diagnostic accuracy. Compared to the original diagnostic criteria, the new criteria quantifies and supports some indicators, which is convenient for clinical application. The sensitivity and specificity of the AGA dermoscopic diagnostic criteria were 98.3% and 96.7%, respectively. In permed curly hair or more basal natural hair volume and early hair diseases in which the clinical manifestations are not apparent, a diagnosis based on clinical diagnosis is insufficient. We can observe some indicators using dermoscopy that cannot be visualized with unaided eyes, which could facilitate the diagnosis of AGA and reduce missed diagnoses. In some patients diffuse alopecia areata does not have the typical patchy hair loss; the hair loss can be evenly distributed throughout the scalp. Telogen effluvium can occur at any age and is clinically characterized by a sudden increase in hair loss without a change in the forehead hair. Under dermoscopy, telogen effluvium shows an increase in single follicle hair units and upright regrowing. 18 The clinical manifestations of diffuse alopecia areata and telogen effluvium were similar to AGA. Diffuse alopecia areata and telogen effluvium are likely to be misdiagnosed and treatment would be delayed without dermatoscopy (Figure 3).
FIGURE 3.
(A1) Clinical photographs of diffuse alopecia areata. (A2) Dermoscopic images of Diffuse alopecia areata shows yellow dots, black dots, broken hairs, and hairless hair follicles. (B1) Clinical photographs of telogen effluvium. (B2) Dermoscopic images of telogen effluvium shows upright regrowing, single hair follicle unit, brown peripilar sign, and hairless hair follicles.
The severity of AGA mainly depends on the number or proportion of different diameter hairs, such as thin, rough, vellus, and intermediate hairs, which can be measured under dermoscopy. Because the number of hairs in each patient is different, we measured the ratio of rough hairs on the vertex/occipital area to determine whether the hair density in the hair loss area of patients was significantly reduced compared to the non‐hair loss area. In addition to thinning of the hair diameter, as proportion of a single hair follicle units increased, the number of hairs decreased, the coverage of hair decreased correspondingly, and hair loss was more severe, so proportion of a single hair follicle units is also a very important indicator. In the current study, among AGA and different severity grades, there were significant differences in proportion of vellus hairs, thin hairs, intermediate hairs, hairs < 0.06 mm, hairs < 0.03 mm, single hair units, and ratio of rough hairs on the vertex/occipital scalp. Furthermore, inter‐group analysis showed that proportion of vellus hairs, hairs < 0.06 mm, hairs < 0.03 mm, and ratio of the rough hairs on the vertex/occipital scalp were significantly different from the three groups and was therefore used as an indicator for grading criteria. Although proportion of vellus hairs was significantly different among different grades of AGA, proportion of vellus hairs was not distinguishable between healthy controls and grade 1 AGA (all <10%). Therefore, vellus hairs was not included. Measuring hairs < 0.03 mm only was needed to calculate proportion of thin and vellus hairs, which is more convenient than < 0.06 mm. Therefore, proportion of hairs < 0.03 mm on the frontal and/or vertex scalp was included. There was no significant difference between grade 1 and 2 in proportion of single hair follicle units, but it had a significant negative correlation with hair coverage, so it was included.
Therefore, the grading criteria focus on three indices that indicate the level of hair coverage of patients. The accuracy of the grading criteria in the study was 96%. The clinical diagnosis tends to underestimate the severity of the patient, which can be related to hair color, perm, length, and hair volume. Moreover, physician evaluations of alopecia severity are unlikely to be completely consistent. Dermoscopic classification can effectively avoid the occurrence of the above situation and improve the accuracy of classification.
5. CONCLUSION
At present, the incidence of AGA is high and the age of onset is decreasing. The treatment requirements of patients are high. It is easy to miss or misdiagnose AGA without dermoscopy and the early diagnosis and treatment of patients can be delayed, which affects prognosis. Clinical grading tends to underestimate AGA severity, and dermoscopic grading complements clinical grading by corresponding to the BASP criteria. This study propose objective and convenient dermoscopic diagnostic and grading standards for AGA with high sensitivity and specificity, which are suitable for different genders and have wide application and high efficiency.
CONFLICT OF INTEREST STATEMENT
The authors declare no conflicts of interest.
IRB APPROVAL STATUS
Reviewed and approved by the First Hospital of Soochow University IRB (approval # 2023 No.517).
ACKNOWLEDGMENTS
We thank International Science Editing (http://www.internationalscienceediting.com) for editing this manuscript.
Wang Y, Ding W, Yao M, Li Y, Wang M, Wang L, et al. Diagnostic and grading criteria for androgenetic alopecia using dermoscopy. Skin Res Technol. 2024;30:e13649. 10.1111/srt.13649
Yuting Wang, Wei Ding, and Manxue Yao contributed equally to this study.
Contributor Information
Mengyao Yang, Email: ymy9392@163.com.
Yueqian Zhu, Email: zhuyueqian0711@126.com.
Naihui Zhou, Email: zhounaihui@163.com.
DATA AVAILABILITY STATEMENT
The data that support the findings of this study are available from the corresponding author upon reasonable request.
REFERENCES
- 1. Wang TL, Zhou C, Shen YW, et al. Prevalence of androgenetic alopecia in China: a community‐based study in six cities. Br J Dematol. 2010;162(4): 843–847. doi: 10.1111/j.1365-2133.2010.09640.x [DOI] [PubMed] [Google Scholar]
- 2. Kanti V, Messenger A, Dobos G, et al. Evidence‐based (S3) guideline for the treatment of androgenetic alopecia in women and in men. J Eur Acad Dermatol Venereol. 2018;32(1):11–22. doi: 10.1111/jdv.14624 [DOI] [PubMed] [Google Scholar]
- 3. Hu Z, Liu Q, Zhang J. Guidelines for the diagnosis and treatment of androgenic alopecia in Chinese people. Chin J Aesth Plast Surg. 2019;30(1):1–5. doi: 10.3969/j.issn.1673-7040.2019.01.001 [DOI] [Google Scholar]
- 4. Norwood OT. Male pattern baldness: classification and incidence.South Med J. 1975;68(11):1359–1365. doi: 10.1097/00007611-197511000-00009 [DOI] [PubMed] [Google Scholar]
- 5. Ludwig E. Classification of the types of androgenetic alopecia (common baldness) occurring in the female sex. Br J Dematol. 1977;97(3):247–254.doi: 10.1111/j.1365-2133.1977.tb15179.x [DOI] [PubMed] [Google Scholar]
- 6. Lee WS, Ro BI, Hong SP, et a1. A new classification of pattern hair loss that is universal for men and women: basic and specific (BASP) classification. J Am Acad Dermatol. 2007;57(1):37‐46. doi: 10.1016/j.jaad.2006.12.029 [DOI] [PubMed] [Google Scholar]
- 7. Zhou C, Zhang J. Chinese androgen alopecia diagnosis and treatment guidelines BASP classification method interpretation. J Dermatology and Venereology. 2016;38(5):325–327. doi: 10.3969/j.issn [DOI] [Google Scholar]
- 8. Zhang X. Correlation of dermoscopy and pathological features in common disorders of hair loss. Clin Dermatol. 2011;40(12):771–774. doi: 10.3969/j.issn.1000-4963.2011.12.034 [DOI] [Google Scholar]
- 9. de Lacharrière O, Deloche C, Misciali C, et al. Hair diameter diversity: a clinical sign reflecting the follicle miniaturization. Arch Dermatol. 2001;137(5):641–646. Arch Dermatol.‐ISSN‐0003‐987x‐137‐5‐dob10023. doi:10‐1001/pubs [PubMed] [Google Scholar]
- 10. Rakowska A, Slowinska M, Kowalska OE, et al. Dermoscopy in female androgenic alopecia: method standardization and diagnostic criteria. Int J Trichology. 2009;1(2):123–130. doi: 10.4103/0974-7753.58555 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11. Wang Y, Li N, Wu Y, Wang L, Yang D. Four fixed points for dermoscope in male androgenetic alopecia: a way to diagnosis and monitor therapy effect. Skin Res Technol. 2023;29(9). doi: 10.1111/srt [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12. Rakowska A. Trichoscopy (hair and scalp videodermoscopy) in the healthy female. Method standardization and norms for measurable parameters. J Dermatol Case Rep. 2009;3(1):14–19. doi: 10.3315/jdcr.2008.1021 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13. Rudnicka L, Olszewska M, Rakowska A, et al. Trichoscopy update 2011. J Dermatol Case Rep. 2011;5(4):82–88. doi: 10.3315/jdcr.2011.1083 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14. Rakowska A, Slowinska M, Kowalska‐Oledzka E, et al. Dermoscopy in female androgenic alopecia: method. Int J Trichology. 2009;1(2):123–130. doi: 10.4103/0974-7753.58555 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15. Köse ÖK, Güleç AT. Clinical evaluation of alopecias using a handheld dermatoscope. J Am Acad Dermatol. 2012;67(2):206–214. doi: 10.1016/j.jaad.2011.08.019 [DOI] [PubMed] [Google Scholar]
- 16. Inui S, Nakajima T, Itami S. Scalp dermoscopy of androgenetic alopecia in Asian people. J Dermatol. 2009;36(2):82–85. doi: 10.1111/j.1346-8138.2009.00593.x [DOI] [PubMed] [Google Scholar]
- 17. Ross EK, Vincenzi C, Tosti A. Video dermoscopy in the evaluation of hair and sclap disorders. J Am Acad Dermatol. 2006;55(5):799–806. [DOI] [PubMed] [Google Scholar]
- 18. Dong Q, Weixing Fan. Differential diagnosis and treatment of three different types of diffuse hair loss. J Clin Dermatol. 2016;45(2):146–149. doi: 10.16761/j.cnki.1000-4963.2016.02.033 [DOI] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
The data that support the findings of this study are available from the corresponding author upon reasonable request.