Alopecia

Introduction

Hair loss (also called alopecia) may occur as thinning of the hair or shedding of hair, and is common in adults.

It is often a cause of great concern to the patient for cosmetic and psychologic reasons.

Hair Growth Cycle

Hair loss disorders are usually due to the hair growth cycle being interrupted at different stages.

During a person's lifetime, each follicle goes through many cycles of anagen, catagen and telogen.

Anagen: A long (2- to 6-year) growing phase
Catagen: A brief (3-week) transitional apoptotic phase
Telogen: A short (2- to 3-month) resting phase

At the end of the resting phase, the hair falls out. Normally, about 50 to 100 scalp hairs reach the end of resting phase each day and fall out.

Classification

Alopecia can be classified as focal or diffuse and by the presence or absence of scarring.

Scarring (cicatricial) alopecia

Is the result of active destruction of the hair follicle. The follicle is irreparably damaged and replaced by fibrotic tissue.
Include chronic lupus erythematosus, lichen planopilaris, central centrifugal cicatricial alopecia, dissecting cellulitis and folliculitis decalvans.

Nonscarring alopecia

Results from processes that reduce or slow hair growth without irreparably damaging the hair follicle.
Are most common and include male baldness, female pattern hair loss, telogen effluvium, alopecia areata and trichotillomania.

Patient Interview

In general, the interview should include

An assessment of the nature of hair loss (e.g. duration, rate of progression, location and pattern, associated symptoms)
The patient's medical history (including medication and supplement use)
The patient's hair care practices, and
The patient's family history

Interpreting Physical Findings in Alopecia

Androgenetic Alopecia (Male-pattern or Female-pattern Hair Loss)

Androgenetic alopecia is the most common cases of alopecia.

It is an age-related change in hair growth that affects people with a genetic predisposition.
Terminal hairs are replaced by shorter and finer miniaturised hairs, due to the effect of androgens on scalp hair follicles.

Androgenetic alopecia does not need treatment. However, many affected people seek treatment for cosmetic reasons.

The main aim of treatment is to slow down further hair loss, and the secondary aim is to stimulate regrowth. Most treatments for androgenetic alopecia take 6 to 12 months to show an effect, and need to continue for years or indefinitely for sustained benefit.

Men - Topical minoxidil 2% or 5% +/- oral finasteride 1 mg
Female - Topical minoxidil 2% or 5% +/- oral spironolactone 50-200 mg daily

NOTE:

With oral finasteride therapy, there is a small risk of sexual dysfunction (e.g. erectile dysfunction, reduced libido) and gynaecomastia (rare).
The typical dose of spironolactone utilized is 200 mg per day, but usually begun at lower dose (e.g. 50 mg per day).
Spironolactone use in female is contraindicated in pregnancy because of the risk of defective virilisation of the male foetus.
In all patients, measure blood pressure, kidney function and liver biochemistry before starting spironolactone, then every 6 to 12 months. Older females may need more frequent monitoring if clinically indicated.

Anagen Effluvium

Anagen effluvium occurs as a result of an acute interruption of the anagen phase and leads to extensive hair loss without transition of follicles into the catagen or telogen phase.

It typically occurs several weeks after chemotherapy or radiation therapy.

Hair loss is usually temporary and is best treated with a wig; when hair regrows, it may be different in colour and texture from the original hair.

Telogen Effluvium

Telogen effluvium is a reactive hair condition that causes excessive hair shedding.

Anagen is prematurely terminated by a triggering event, and hairs enter the telogen rest phase en masse.

Hair loss that occurs 3 to 4 months after a major stressor (pregnancy, major febrile illness, surgery, medication change, or severe psychologic stressor) suggests a diagnosis of telogen effluvium.

Hair loss due to telogen effluvium is usually temporary and abates after the precipitating agent is eliminated.

Alopecia Areata

Alopecia areata is a complex polygenic autoimmune disorder, and unknown environmental triggers cause its expression.

These unknown triggers signal the anagen hairs in the affected area to convert to telogen. Hair prematurely stops growing and sheds rapidly, causing patches of alopecia.
The pathogenesis involves inflammation of anagen hair bulbs.

NOTE: Sometimes, it can lead to the complete loss of hair on the scalp (alopecia totalis) or, in extreme cases, the entire body (alopecia universalis).

Alopecia aerata is characterized by unpredictable remission and relapse. A patch may

Regrow hair spontaneously
Stay the same for many months
Enlarge and coalesce with other patches

Treatment for alopecia areata includes topical, intralesional, or, in severe cases, systemic corticosteroids, topical minoxidil, topical anthralin, topical immunotherapy (diphenylcyclopropenone or squaric acid dibutylester), or methotrexate.

Also, provide emotional and social support to the patient when waiting for hair to regrow, and also if hair does not regrow.

Trichotillomania

Trichotillomania is an impulse control disorder in which individuals repeatedly pluck hairs from the scalp or other hair-bearing areas.

The areas of alopecia may have irregular, bizarre shapes.

In most children, it is usually a benign habit that resolves with age, but sometimes it is a response to stress at home or school.

In contrast, trichotillomania in adults is usually associated with a psychological disorder (e.g. anxiety, obsessive compulsive disorder) - refer to a psychologist or psychiatrist.

Supplements

Biotin supplements may help with hair growth in people with vitamin B7 deficiency.

Additionally, caffeine topical formulations have been investigated for their role in managing androgenetic alopecia.

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