Guideline for Diagnostic Evaluation in Androgenetic Alopecia

Diagnostic Techniques and Clinical Documentation

Pull Test

The pull test is an examination that is easy to perform and to repeat, to roughly judge active hair shedding. Briefly, 50–60 hairs are grasped by thumb, index and middle fingers. While the hairs are tugged away, the fingers slide along the hair shaft. The pull test is positive when more than 10% of the grasped hair can be pulled out.^[36] The test has a large inter-observer variation and is influenced by shampooing so that each examiner should personally standardize their own procedure. The pull test should be performed in the right and left parietal, frontal and occipital regions and in the visibly affected areas, as shortening of the cycle increases telogen rates and the pull test becomes positive. The pull test in different scalp regions is useful in excluding diffuse effluvium.^[36]

In patients with AGA the pull test is positive only in the active phase with increased telogen hairs in the affected area. It may be frontally accentuated or diffusely positive. A diffuse positive pull test requires further diagnostic tests to exclude diffuse telogen effluvium.

The pull test is usually negative in AGA, except in active periods when there can be a moderate telogen hair shedding in a pattern distribution. However, even with a diffusely positive pull test such as in telogen effluvium or diffuse alopecia areata, underlying AGA may be present.

Dermoscopy or Loupe

Dermoscopy or loupe are noninvasive techniques, which improve examination of scalp skin and hair by magnification, e.g. assessment of hair follicle openings to exclude scarring alopecia is facilitated. In combination with video mounting (videodermoscopy) the storing of diagnostic findings for further controls can be taken into account.^[36,45]

In AGA increased hair diameter diversity and an increased number of vellus hairs can be seen. Less common are peripilar signs, reflecting the presence of perifollicular infiltrates, and yellow dots more prevalent in alopecia areata.^[35]

Global Photography

Global photographs are helpful tools to evaluate objectively the course of hair growth, hair volume and hair density in clinical studies and for long-term follow-up in daily practice. In clinical studies the photographs of vertex, mid-pattern, frontal and temporal regions are standardized by using a stereotactic device assuring a constant view, magnification and lightening for follow-up assessment.^[46] It was agreed that global photography is suitable for daily clinical practice only when a standardized technique is used.

Automatic Digitalized System for Hair Density and Anagen/Telogen Hairs (Phototrichogram/Trichoscan)

These systems for measurement of hair density and the anagen/telogen ratio can be used for diagnosis and follow-up, where available, but their use is mainly as a tool for clinical studies. In AGA the frontal hair density is decreased compared with the occipital density. The anagen/telogen ratio is normal or decreased.^[47] To ensure reproducibility, tattoos identifying the area are required.^[36] These techniques are helpful for long-term follow-up and quantification.^[48,49]

Trichogram

The trichogram is indicated only in individual cases where a loose anagen syndrome or anagen-dysplastic effluvium is suspected. A trichogram should be used only by dermatologists who are familiar with this technique and perform it routinely.^[50]

Biopsy

The scalp biopsy is an essential instrument in the diagnosis of cicatricial and selected forms of noncicatricial alopecia.^[51] A biopsy, mostly performed as a 4-mm cylindrical punch, is indicated in AGA only in cases where the diagnosis is uncertain, e.g. where scalp changes suggestive of cicatricial alopecia or diffuse alopecia areata are present. Scalp biopsies should be reported by dermatopathologists who are experienced in hair pathology using both vertical and horizontal sectioning.

Site of Biopsy The preferred area for biopsy is the central scalp in an area representative of the hair loss process. Biopsies should not be taken from the bitemporal area as this region may have miniaturized hairs independent of AGA.

Type of Biopsy Two 4-mm punch biopsies following the direction of the hair shafts are taken lateral to the midline deep into the subcutaneous fat where anagen hair bulbs are located. One biopsy is processed for conventional vertical sectioning; the other is sectioned horizontally with respect to the skin surface.^[51–53]

Horizontal sectioning allows a rapid assessment of hair follicle numbers, diameter, grouping and morphology.^[54] In AGA, there is an increased number and proportion of miniaturized (vellus-like) hair follicles. The ratio of terminal to vellus-like hair follicles is typically < 3 : 1 in AGA-affected areas compared with > 7 : 1 in the normal scalp.^[53] Other features include an increased telogen : anagen ratio and an increase in the number of follicular stelae (tracts beneath miniaturized follicles).^[55] A mild perifollicular lymphohistiocytic infiltration primarily around the upper follicle as well as perifollicular fibrosis may also be seen.^[20]

Table 1. Diagnostic evaluation form for androgenetic alopecia
1. History
Age	___ years
Sex	□ Male
□ Female
First manifestation of hair loss	Age: ___
Course of hair loss	□ Acute
□ Chronic – Intermittent
□ Chronic – Persistent
Complaining of increased shedding of hair	□ Moderate
□ Severe
□ No
Complaining of increased thinning of hair	□ Diffuse
□ Localized
□ No
Itching	□ Yes □ No
Dandruff	□ Yes □ No
Trichodynia	□ Yes □ No
Family history of androgenetic alopecia	□ Yes
□ Mother/maternal side □ Father/paternal side
□ No
Concomitant diseases (chronic, autoimmune, recently diagnosed, with possibly chronologic relation to hair loss)	___________
Previous surgery	___________
Eating behaviour
Strictly vegetarian diet	□ Yes □ No
Crash diet or eating behaviour disorders	□ Yes □ No
Important weight loss > 5–10 kg	□ Yes □ No
Weight	___________
Height	___________
Drug history (e.g. pro-androgenic, antithyroid, anti-epiletics, β-blocker, chemotherapeutics, supplements)	Please provide details: ___________
Smoking	□ Yes □ No
Only in women
Menstrual cycle	□ Regular □ Irregular
Menopause	___________
Oligomenorrhoea	□ Yes □ No
Amenorrhoea	□ Yes □ No
Since when	___________
Hormonal contraception	□ Yes □ No
Hormonal replacement therapy	□ Yes □ No
Fertility treatment	□ Yes □ No
Specify drug and duration	___________
Succesful and unsuccessful pregnancies	___________
Excessive facial and/or body hair growth	□ Yes □ No
Skin changes (acne)	□ Yes □ No
Seborrhoea of scalp/skin	□ Yes □ No
In children and adolescents
Hair loss	□ Congenital □ Acquired
Signs of pubertal development	□ Yes □ No
If yes, at which age	___________
□ Mature □ Premature
2. Clinical examination
Hair density	□ Normal
□ Decreased
□ Pattern distribution
□ Alopecic patches
Scalp skin	□ Normal
□ Erythema
□ Scaling
□ Seborrhoea
□ Pustules
□ Signs of scarring
□ Others (e.g. psoriasis, pigmentation)
Eyebrows/eyelashes	□ Normal
□ Abnormal
Facial and body hair	□ Normal
□ Excessive hair growth/hirsutism
□ Decreased axillary hair
□ Decreased pubic hair
Signs of acne	□ Yes □ No
3. Laboratory
Iron, ferritin	□
TSH	□
Blood haemoglobin	□
TPHA/RPR if indicated by clinical DD	□
In women only, if hormonal dysregulation is suspected
FAI [total testosterone (nmol L⁻¹) × 100 SHBG (nmol L⁻¹)]	□
DHEAS	□
Prolactin	□
4. Hair examination tests
Pull test	□
(Video-) Dermoscopy/loupe	□
Hair shaft examination	□
Trichogram	□
Biopsy	□

Table 1. Diagnostic evaluation form for androgenetic alopecia

1. History

Age

___ years

Sex

□ Male

□ Female

First manifestation of hair loss

Age: ___

Course of hair loss

□ Acute

□ Chronic – Intermittent

□ Chronic – Persistent

Complaining of increased shedding of hair

□ Moderate

□ Severe

□ No

Complaining of increased thinning of hair

□ Diffuse

□ Localized

□ No

Itching

□ Yes □ No

Dandruff

□ Yes □ No

Trichodynia

□ Yes □ No

Family history of androgenetic alopecia

□ Yes

□ Mother/maternal side □ Father/paternal side

□ No

Concomitant diseases (chronic, autoimmune, recently diagnosed, with possibly chronologic relation to hair loss)

___________

Previous surgery

___________

Eating behaviour

Strictly vegetarian diet

□ Yes □ No

Crash diet or eating behaviour disorders

□ Yes □ No

Important weight loss > 5–10 kg

□ Yes □ No

Weight

___________

Height

___________

Drug history (e.g. pro-androgenic, antithyroid, anti-epiletics, β-blocker, chemotherapeutics, supplements)

Please provide details: ___________

Smoking

□ Yes □ No

Only in women

Menstrual cycle

□ Regular □ Irregular

Menopause

___________

Oligomenorrhoea

□ Yes □ No

Amenorrhoea

□ Yes □ No

Since when

___________

Hormonal contraception

□ Yes □ No

Hormonal replacement therapy

□ Yes □ No

Fertility treatment

□ Yes □ No

Specify drug and duration

___________

Succesful and unsuccessful pregnancies

___________

Excessive facial and/or body hair growth

□ Yes □ No

Skin changes (acne)

□ Yes □ No

Seborrhoea of scalp/skin

□ Yes □ No

In children and adolescents

Hair loss

□ Congenital □ Acquired

Signs of pubertal development

□ Yes □ No

If yes, at which age

___________

□ Mature □ Premature

2. Clinical examination

Hair density

□ Normal

□ Decreased

□ Pattern distribution

□ Alopecic patches

Scalp skin

□ Normal

□ Erythema

□ Scaling

□ Seborrhoea

□ Pustules

□ Signs of scarring

□ Others (e.g. psoriasis, pigmentation)

Eyebrows/eyelashes

□ Normal

□ Abnormal

Facial and body hair

□ Normal

□ Excessive hair growth/hirsutism

□ Decreased axillary hair

□ Decreased pubic hair

Signs of acne

□ Yes □ No

3. Laboratory

Iron, ferritin

□

TSH

□

Blood haemoglobin

□

TPHA/RPR if indicated by clinical DD

□

In women only, if hormonal dysregulation is suspected

FAI [total testosterone (nmol L⁻¹) × 100 SHBG (nmol L⁻¹)]

□

DHEAS

□

Prolactin

□

4. Hair examination tests

Pull test

□

(Video-) Dermoscopy/loupe

□

Hair shaft examination

□

Trichogram

□

Biopsy

□

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